Front facing railway camera

Transcription

Lebanese University
FACULTY OF ENGINEERING
BRANCHE 1
Order no. 39/875/G1-EE/2013
Final Project
Realized by
Mohamad Azmi CHAHAL
To obtain an
Engineering Diploma in Electricity and Electronics
Option Control and Industrial Computing
Front facing railway camera
Directed by:
Prof. Cédric Bornand
Argued before the jury:
Dr. Haissam Ziade
Dr. Bachar El-Hassan
Dr. Khaled Mechref
Session July 2013
Acknowledgment
First, I want to thank Prof. Bornand and Dr. Ziade for proposing this project and giving
me this wonderful opportunity.
Thanks to Mr.Medwed for giving me valuable advices and directing me to the right choices, to
Mr.Perrin for preparing the materials and helping me with the tests.
Thanks to Mr.David and his crew for building and helping with the mechanical designs.
Also, thanks to Dr.Falou for helping me with the socket programing part and sending me the
code examples.
Finally, a big thanks to all the professors at the Lebanese university and the direction of the
faculty, to my friends and family…I wouldn’t be here without you.
Institute society
The eMbedded Information Systems (MIS) Institute, HEIG-VD, around the axes of
acquisition, communication and signal processing, designs and implements embedded systems,
by taking into account the cost, the power consumption and the system’s behavior in real time
applications.
Since September 2003, MIS was certified by the Swiss association for “Quality System
management”, by following the criteria’s of the norm ISO 9001:2000. This certification is
related to three major activities of MIS:



Applied research and development
Services
In-service training
MIS has an area of expertise in the field of electronics, vision, acoustic, embedded systems,
algorithms… Along this, MIS takes on tasks related to industrial system designs, like a front
facing train camera, a power management system…
Abstract
The project, codenamed Eyesrail_Dig, is for a recycling company (Tridel; LausanneSwitzerland). This company uses a train to transport the garbage that needs recycling, on a
private railway road. The SBB-CFF-FSS (Swiss Federal Railways) train system used pushes
the cargos containing the garbage to the factory, where they are emptied, and then pull them
back on the same track to refill them. The problem is that when going toward the factory, the
driver is completely blind. To solve this, Tridel, as well as all other Swiss companies that use
the SBB cargo trains, uses two employees: one is in the driving chamber, and the other standing
at the tip of the last cargo wagon, guiding the driver by radio. This method of driving is very
dangerous. The solution is to replace the person standing at the tip of the train with a camera
that sends the video stream wirelessly to the driver’s chamber. The system must be designed
with EN50155 norm (Railway applications - Electronic equipment used on rolling stock)
approved parts. The main task was to make complete mechanical and electrical designs, along
with a Bill of Materials (BOM). A complete concept of an improved system, powered by a dual
axis motorized solar panel, with the corresponding charger circuit, has been put in place.
Key words: SBB cargo (Swiss Federal Railways) – IP camera – Antenna – Access pointEN50155 (Railway applications - Electronic equipment used on rolling stock) – Motorized
solar panel
Résumé
Ce projet est pour une compagnie de recyclage (Tridel; Lausanne-Suisse). Cette
compagnie utilise un train pour transporter les déchets à recycler, sur une route ferroviaire
privée. Le système de train SBB-CFF-FSS (Chemins de fer fédéraux suisses) utilisé pousse les
wagons contenant les déchets vers l’usine, où ils seront vidés, et puis les tire sur le même
chemin. Le problème est que quand il a comme destination l’usine, le conducteur est
complètement aveugle de ce qui est en avant. Pour résoudre ce problème, Tridel, comme toutes
les autres compagnies qui utilisent les trains SBB cargo, ont besoin de deux employés: un pour
conduire le train, et l’autre debout sur l’extrémité du dernier wagon, guidant le conducteur par
radio. Cette méthode de conduction est très dangereuse. La solution est de remplacer le
deuxième employé par une caméra qui envoie le flux vidéo par un moyen sans fil vers la
chambre du conducteur. Le système doit être conçu en respectant la norme EN50155 (Les
applications de chemin de fer - L'équipement électronique utilisé sur les matériels roulant
ferroviaire). Le but principal est de concevoir un système complet avec les schémas électrique
et mécanique correspondantes, les listes des matériaux choisis (BOM). Une conception
complète d’un système amélioré, alimenté par un panneau solaire motorisé sur deux axes, avec
le circuit de charge correspondant, a été finis.
Mots clés: SBB cargo – caméra IP – Antenne – Access point - EN50155 – Panneau solaire
motorisé
Table of contents
General introduction ............................................................................................................... 6
Chapter I-Presented solutions ................................................................................................ 8
I.1. Problem description ......................................................................................................... 8
I.2. Old system description ..................................................................................................... 8
I.3. Points to improve the system ........................................................................................... 9
I.3.1. Frequency band ......................................................................................................... 9
I.3.2. Modulation technique................................................................................................ 9
I.4. M12 vs RJ45 .................................................................................................................... 9
I.5. Power over Ethernet ....................................................................................................... 10
I.6. Other analogue system ................................................................................................... 10
I.6.1. Solution 2.4 GHz .................................................................................................... 10
I.6.2. Solution 5 GHz ........................................................................................................ 11
I.7. Digital solutions ............................................................................................................. 11
I.7.1. Industrial system (PoE-M12) .................................................................................. 11
I.7.2. Industrial system (PoE-RJ45) ................................................................................. 12
I.7.3. Industrial system (non PoE) .................................................................................... 12
I.7.4. Current LCD screen (PoE camera/antenna) ............................................................ 13
Chapter II-Camera side design............................................................................................. 15
II.1. Chosen components ...................................................................................................... 15
II.1.1. SNB-1001P ............................................................................................................ 15
II.1.2. TP-Link TLWA7510N .......................................................................................... 16
II.1.3. OCH2 enclosure .................................................................................................... 16
II.1.4. Battery ................................................................................................................... 16
II.2. OCH2 fixation .............................................................................................................. 17
II.3. Configuration ................................................................................................................ 18
II.3.1. TL-WA7510N ........................................................................................................ 18
II.3.2. IP camera ............................................................................................................... 18
II.4. Conclusion .................................................................................................................... 18
Chapter III-Locomotive side design ..................................................................................... 19
III.1. Design overview ......................................................................................................... 19
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III.2. Smart LCD .................................................................................................................. 19
III.2.1. TEN 40-4812WIR ............................................................................................... 20
III.2.2. TEN 5-1211 .......................................................................................................... 20
III.2.3. Interior design ....................................................................................................... 21
III.3. Configuration .............................................................................................................. 22
III.3.1. TL-WA7510N ...................................................................................................... 22
III.3.2. Raspberry PI ......................................................................................................... 22
III.4. Conclusion ................................................................................................................... 22
Chapter IV-Solar panel design ............................................................................................. 23
IV.1. Introduction ................................................................................................................ 23
IV.1.1. Single axis ........................................................................................................... 23
IV.1.2. Dual axis ............................................................................................................... 23
IV.1.3. Energy generation comparison ............................................................................. 24
IV.2. Solar tracker ............................................................................................................... 24
IV.2.1. Description .......................................................................................................... 24
IV.2.2. Tracker components ............................................................................................. 25
IV.3. Microcontroller choice - Arduino nano ...................................................................... 25
IV.3.1. Description .......................................................................................................... 25
IV.3.2. Power .................................................................................................................... 26
IV.4. Sensor design ............................................................................................................. 26
IV.5. Stepper motor ............................................................................................................. 27
IV.5.1. Types of steppers ................................................................................................. 27
IV.5.2. Bipolar motor control-SN754410......................................................................... 29
IV.5.3. Motor and microcontroller interface .................................................................... 29
IV.5.4. Motor ratings and fixation .................................................................................... 30
IV.6. Tracker algorithm and block diagram ........................................................................ 30
IV.6.1. Algorithm ............................................................................................................ 30
IV.6.2. Block diagram ...................................................................................................... 31
IV.7. Voltage regulator design ............................................................................................ 32
IV.7.1. Solar panel’s specifications ................................................................................. 32
IV.7.2. Maximum Power Point......................................................................................... 32
IV.7.3. Circuit design ...................................................................................................... 33
IV.7.4. BQ24650 .............................................................................................................. 34
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IV.7.5. TPS55340 ............................................................................................................ 34
IV.7.6. TPS84620 ............................................................................................................ 34
IV.8. Conclusion ................................................................................................................. 34
Chapter V-System test ........................................................................................................... 35
V.1. Test 1 ........................................................................................................................... 35
V.2. Test 2 ........................................................................................................................... 35
V.3. Test conclusion ............................................................................................................ 36
Conclusion .............................................................................................................................. 37
Annex A-Materials comparison ............................................................................................ 38
Annex B-Mechanical and electrical design .......................................................................... 54
Annex C-Configurations ....................................................................................................... 70
Annex D-Capacitor choice .................................................................................................... 76
Annex E-Raspberry PI configuration .................................................................................. 78
Annex F-Electronic circuit .................................................................................................... 81
Annex G-BOMs ...................................................................................................................... 97
Annex H-Overo gumstix ...................................................................................................... 103
References ............................................................................................................................. 113
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Figures and tables list
Figure I.1. Problem presentation ............................................................................................ 7
Figure I.2. Solution presentation ............................................................................................ 8
Figure I.3. View of the analogue system ................................................................................ 8
Figure I.4. RJ45-M12 connectors ......................................................................................... 10
Figure I.5. Solution 2.4 GHz block diagram ........................................................................ 10
Figure I.6. Solution 5 GHz block diagram........................................................................... 11
Figure I.7. Industrial system M12 solution block diagram ................................................ 11
Figure I.8. Industrial system RJ45 solution block diagram ............................................... 12
Figure I.9. Industrial system non PoE solution block diagram ........................................ 12
Figure I.10. Block diagram of the solution based on using the current LCD .................. 13
Figure I.11. Chosen solution block diagram........................................................................ 14
Figure II.1. Design schematic-camera side .......................................................................... 15
Figure II.2. Samsung SNB-1001P ......................................................................................... 15
Figure II.3. TP-Link TL-WA7510N ..................................................................................... 16
Figure II.4. OCH2 enclosure ................................................................................................. 16
Figure II.5. Yellow hook on SBB cargo trains..................................................................... 17
Figure II.6. On/Off magnet ................................................................................................... 17
Figure II.7. Magnet fixation .................................................................................................. 18
Figure III.1. Design schematic-locomotive side ................................................................... 19
Figure III.2. LCD screen ....................................................................................................... 19
Figure III.3. Black box content ............................................................................................. 20
Figure III.4. Black box interior design................................................................................. 21
Figure IV.1. Rotation axes of solar panel ............................................................................ 23
Figure IV.2. Power efficiency chart...................................................................................... 24
Figure IV.3. Solar tracker block diagram ........................................................................... 24
Figure IV.4. Arduino pins ..................................................................................................... 25
Figure IV.5. Sensor circuit design ........................................................................................ 26
Figure IV.6. Sensor fixation and protection ........................................................................ 27
Figure IV.7. Sun rays hitting the solar panel ...................................................................... 27
Table IV.1. Comparison between stepper motors............................................................... 28
Figure IV.8. Speed vs. torque chart...................................................................................... 28
Figure IV.9. H-bridge used to control bipolar motors ....................................................... 29
Figure IV.10. SN754410 interface with the motor and the Arduino ................................. 29
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Figure IV.11. Gears on a mechanical dish ........................................................................... 30
Figure IV.12. Tracker algorithm chart ................................................................................ 30
Figure IV.13. Solar tracker block diagram ......................................................................... 31
Figure IV.14. Used solar panel.............................................................................................. 32
Figure IV.15. Solar cell I-V curve in varying sunlight ....................................................... 33
Figure IV.16. Charger circuit overview ............................................................................... 33
Figure V.1. Box fixed on the yellow hook during test ......................................................... 35
Figure V.2. Tunnel used by Tridel ....................................................................................... 36
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General introduction
The project, Eyesrail_Dig, is for a recycling company (Tridel; Lausanne-Switzerland).
This company uses a train to transport the garbage that needs recycling, on a private railway
road. The SBB-CFF-FSS (Swiss Federal Railways) train system used pushes the cargos
containing the garbage to the factory, where they are emptied, and then pull them back on the
same track to refill them.
The problem is that when going toward the factory, the driver is completely blind. To solve
this, Tridel, as well as all other Swiss companies that use the SBB cargo trains, uses two
employees: one is in the driving chamber (locomotive side), he is completely blind of what is
in front of the train, and the other employee standing at the tip of the last cargo wagon, guides
the driver by radio. It is a very dangerous method, especially during the winter because the
guiding person must stay out in minus zero degrees for a long period of time, with cold winds
hitting him all along the way because of the train speed.
MIS suggested to replace the guiding person with a camera system that will send the video
signal to the driving chamber wirelessly. A system has already been designed, it is an analogue
2.4 GHz system. The track which TRIDEL uses is made of two parts, one in open air and the
other inside a tunnel. In the tunnel part, the system worked very well, but once in open air, the
video signal was cut off, and when it arrived, it was very noisy and not viewable. This is due
to the noise coming from the commutation of the rail tracks, and from other trains passing by.
The first part of the project was to present solutions to improve the current system, then once
a solution has been chosen, to design and implement a “camera-transmitter/receiver-screen”
outdoor system to transmit the image from the end of the train to the driver’s chamber. The
system must be designed with EN50155 norm (Railway applications - Electronic equipment
used on rolling stock) approved parts. The main task was to make complete mechanical and
electrical designs, along with a list of the chosen materials (BOM).
The second part is to design a motorized solar panel to recharge the battery feeding the camera,
transmitter and antenna part, along with electrical and mechanical schemes, a list of the chosen
materials, the algorithm used to follow the sun rays and the design of the charging circuit.
The third part was a programming task. MIS has designed a Linux based camera equipped with
Wi-Fi capability. The idea is to develop a truly autonomous camera, fed by a solar panel, which
records images as long as there is motion and sends them via Wi-Fi to a remote PC. The solar
panel and the motion detection part were already done by previous students, my task was to
develop a program to send the images via Wi-Fi.
In this report, I will first present the reasons why I have designed the system in a certain manner,
detailing the technical causes and the electrical and mechanical schemes, then I will present a
concept of a motorized solar panel to be implemented on the system, along with the sun
tracking algorithm, and finally I will present the algorithm used to send the images from the
camera via Wi-Fi.
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Chapter I – System overview
I.1.Problem description
Fig.I.1. Problem presentation
As you can see from the above picture, the track used by Tridel is comprised of 2 parts,
one in open air where the train yard is, and the other inside the tunnel. The problem is that
when going toward the factory, the driver can’t see in front of him and needs the second
employee to guide him.
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Fig.I.2. Solution presentation
We can see from figure I.2. the solution to this problem. It is to replace the second employee
with a camera facing the railway track, which sends the video stream to the driver’s chamber.
I.2. Old system description
The already designed system was made by two engineers that previously worked at the
institute. It was based on the AWV365 analogue transmitter/receiver system, working on 2.4
GHz, coupled with D-link ANT24-0801 antennas.
Fig.I.3. View of the analogue system
As you can see from figure I.1, the old system was fixed at the end of the last cargo wagon, on
the part that connects to other cargos to push them forward. The fixture was not very robust
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since it is a simple metallic band that wraps around the metallic cylinder. It was very heavy
(approximately 7 Kg) since it is made completely out of metal.
The main problems with the old system were first that it took a long time to be fixed and
unfixed, and Tridel needed to move the camera from one wagon to the other in the shortest
time possible. The second problem was that the system cut off all the time when it functioned
in open air, and sometimes inside the tunnel, when the antennas were not facing each other.
I.3. Points to improve the system
I.3.1. Frequency band
The biggest advantage of 5 GHz over 2.4 GHz is that the former’s not susceptible to
interference from the myriad wireless devices that uses 2.4 GHz, which are almost all of the
devices we find everywhere such as Bluetooth devices, microwave ovens, alarm systems,
wireless speakers…
The 5 GHz has a wider wireless spectrum available compared to the 2.4 GHz[1], which leads to
significantly better performance as the 5 GHz is commonly used for usage that requires
uninterrupted throughput. That is why it is recommended for media streaming, or to transfer
music, pictures, and video throughout, which is our case.
As for the other band, which is 800 MHz, it was forbidden by law to use it in our system
because it would interfere with other transmissions (digital terrestrial television, mobile
broadband).
I.3.2. Modulation technique
The major advantage that digital modulation has over analog transmission is how it
achieves greater fidelity. With analog modulation, any noise or interference that falls in the
given
frequency bandwidth gets mixed with the actual signal. Although there are a number of ways
to mitigate noise, it will still cause some amount of degradation. Because digital modulation
only recognizes 0’s and 1’s, any noise is virtually eliminated once the receiver discerns whether
a “0” or a “1” was transmitted. Unless the signal is very badly distorted, the output signal will
be literally identical to what was transmitted. So, a system based on digital modulation is a
good choice to avoid losing the image.
I.4. M12 vs. RJ45
Industrial Ethernet cabling requires connection solutions that are sturdy and reliable.
The network plugs and sockets used so effectively and cheaply in the office are often not
suitable in industrial systems where the connections are frequently subjected to humidity,
drastic temperature changes, vibration and shock.
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Fig.I.4. RJ45-M12 connectors
As you can see in figure I.4, the M12 connectors are fixed via a thread to the plug, so they hold
very firmly to it unlike the RJ45 connectors. The M12 4-pin plug connector with D-coding has
already been defined as an Industrial Ethernet standard according to IEC 61067–2–101
Amendment 1.
But due to the fact that the access points equipped with M12 connectors are much more
expensive (more than 10 times) than the ones with RJ45, and the fact that the cables are also
much more expensive, we were obligated to use an RJ45 access point with embedded antennas.
I.5. Power over Ethernet
Power over Ethernet technology describes a system to pass electrical power over
Ethernet cabling, along with data. This means that a network device can be powered and
operated using the same cable. [2]
There are two standards for POE:
The original IEEE 802.3af-2003 PoE standard provides up to 15.4 W of DC power
(minimum 44 V DC and 350 mA) to each device. Only 12.95 W is assured to be available at
the powered device as some power is dissipated in the cable.
The updated IEEE 802.3at-2009 PoE standard also known as PoE+ or PoE plus, provides up
to 25.5 W of power.
I.6. Other analogue solutions
I.6.1. Solution 2.4 GHz
Fig.I.5. Solution 2.4 GHz block diagram
We see in figure I.5. the block diagram of the solution based on a 2.4 GHz analogue
system. It consists of using the same camera, LCD screen and the antennas but change the
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transmitter/receiver couple to another one with a higher emission power, digital modulation
and a better sensibility at the reception. Several manufacturer propose products that are more
powerful than the Tx/Rx couple that the old system used for a price ranging from 45 to 430
CHF. It’s the most cost effective solution
I.6.2. Solution 5 GHz
Fig.I.6. Solution 5 GHz block diagram
We see in figure I.6. the block diagram of the solution based on a 5 GHz analogue
system. It consists of keeping the same camera, the same LCD screen but change the antennas
to a 5 GHz ones, transmitter/receiver couple to another one that works on 5 GHz band, with a
higher emission power, digital modulation and a better sensibility at the reception. Several
manufacturer propose products that are more robust than the Tx/Rx couple currently used and
that functions at 5 GHz for a price ranging from 57 to 260 CHF. The advantage of this solution
is that the 5 GHz band is less noisy in comparison with 2.4 GHz.
I.7. Digital solutions
All of the following solutions can be used for both 2.4GHz and 5 GHz frequency.
I.7.1. Industrial system (PoE-M12)
Fig.I.7: Industrial system M12 solution block diagram
We see in figure I.7. the block diagram of the solution based on a complete industrial
system, powered by an M12 PoE switch, that displays on a rugged industrial screen.
Advantages: -Low power consumption
-Rugged industrial system
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-Highly immune to vibrations and noises
-100% compatible with the EN50155 norm
Disadvantages: -High cost (~5000$)
I.7.2. Industrial system (PoE-RJ45)
Fig.I.8. Industrial system RJ45 solution block diagram
We can see in figure I.8. the block diagram of the solution based on an industrial
system powered by an RJ45 PoE switch, with a rugged industrial screen. RJ45 switches have
lower immunity to vibrations but are much cheaper. (~500$ difference per switch).
Advantages: -Low power consumption
-Rugged industrial system
Disadvantages: -High cost (~4000$)
-Lower immunity to vibrations (compared to M12 switches)
I.7.3. Industrial system (non PoE)
Fig.I.9. Industrial system non PoE solution block diagram
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We can see in figure I.9. the block diagram of a system powered by a non-PoE switch,
that uses PoE injectors to provide power. We will use RJ45 because there are not any M12
injectors.
Advantages: -Lower cost (compared to previous solutions)
Disadvantages: -Higher power consumption (due to the addition of 2 injectors)
-More complexity to the system (several DC-DC/AC-DC converters will be
used to feed the injectors and the switches)
I.7.4. Current LCD Screen (PoE camera/antenna)
Fig.I.10. Block diagram of the solution based on using the current LCD screen
We can see in figure I.10. the block diagram of a solution based on using the current
LCD screen, with PoE enabled camera and antenna.
In this solution we will use a PoE RJ45 switch with splitters to obtain power and Ethernet
separately. The power will be used to feed the LCD screen and the Small Board Computer
(SBC) and the Ethernet to provide data to it.
Advantages: -Equilibrium between number of components and cost
-Usage of the current LCD screen
Disadvantages: -Not 100% immune to vibrations, noise and temperature variations
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I.8. Chosen solution
Fig.I.11: Chosen solution block diagram
In figure I.11, we can see the block diagram of the chosen solution, based on using the
current LCD screen, with a camera and an access point with embedded antenna that works on
12 VDC. The reason we need 12 VDC is the fact that almost all IP cameras work on that
voltage, and that way we can feed the camera side part of the system directly from a battery,
without dissipating any power in DC to DC converters.
On the locomotive side, we will use a small board computer to decode the signal and feed it to
the LCD screen that was used in the analogue system.
I.9. Conclusion
After we decided to design the system according to the above solution, we need to
choose the appropriate materials, for the camera side, and detail the electrical and mechanical
designs along with the configurations of the parts.
Note: -Refer to Annex A to view the comparison lists between available products
-In all of the report, camera side refers to the box where the camera will be put, and locomotive side refers
to the train driver’s chamber
-The blocks in white are the products that needs to be bought and in black are the ones we already have.
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Chapter II – Camera side design
II.1. Chosen components
Fig.II.1. Design Schematic-camera side
In figure II.1. we see the block diagram of the camera side. A battery will power the
IP camera and the PoE injector of the antenna. The PoE injector will provide data and power
to the antenna on a single Ethernet cable.
II.1.1. SNB-1001P
Fig.II.2. Samsung SNB-1001P
The Samsung’s SNB-1001P seen in figure II.2 is a discreet general purpose VGA
network box camera. The chosen camera must be of compact size to fit inside the OCH2 box,
does not consume a lot of power and has the day/night mode feature, this was essential since
there is a part of the train track that goes inside a tunnel. The chosen camera was a low cost
one, having a dimension of 74.3x54.5x114.4mm, consumes a maximum of 3.4 Watts at 12
VDC and has the day/night mode feature. For our application, going up to HD resolution is not
15
beneficial since the driver only needs to see the track, and VGA resolution is more than enough
for this purpose.
II.1.2. TP-Link TL-WA7510N
Fig.II.3. TP-Link TL-WA7510N
In figure II.3, we see TP-Link TL-WA7510N, an access point with embedded antennas.
As we previously said, the access point/antenna must be a 5 GHz one that is powered by 12
VDC. The TP-Link TL-WA7510N is powered by a passive 12 VDC Power over Ethernet
injector. It has a high output transmission power and its reception sensitivity is optimized. It
uses an embedded directional antenna, which was essential to limit the amount of noise
produced by the system. With its weatherproof enclosure and lightning protection, its operating
temperature of -30°C -> 70°C, it is suitable for outdoor applications.
II.1.3. OCH2 enclosure
Fig.II.4. OCH2 enclosure
Figure II.4 shows the enclosure in which the camera side system will be held. It’s a
weatherproof, lockable enclosure used for cameras. It does not weight a lot since it’s made out
of heavy-duty aluminum. With its dimensions of 33x13.2x10.4cm, we can easily fit the camera
with a high capacity battery inside it.
II.1.4. Battery
We need a battery that is enough to power the system during the work hours. When the
work hours are finished, the employees will put the camera box to charge during the night. The
work hours are usually 9 hours. During them, there are a lot of times where the camera is turned
off, which is when waiting for the train to be fixed on the wagons and when going from the
16
factory toward the yard. We need a battery with enough capacity to power the system during
the work hours.
The chosen battery is a 12VDC 9800mAh lithium ion one. It has a protection circuit against
overcharging, over discharging and over-current. Due to its internal charging circuit, it can be
charged directly using a normal 220VAC to 12 VDC adapter.
The maximum power consumed by the access point is 8 Watts, and by the camera is 3.4 Watts.
So in theory, the system should run at least 10.3 straight hours.
II.2. OCH2 fixation
Fig.II.5. Yellow hook on SBB cargo trains
Figure II.5. shows a standard yellow hook on the sides of all the cargo wagons in
Western Europe. The OCH2 will be fixed on this hook, but a major criteria was to design a
certain fast way to hook and unhook this box, because it needs to be moved from one wagon
to the other all day long. After a discussion with the mechanical technician of HEIG-VD, we
were able to design a fixation based on a switchable magnet.
Fig.II.6. ON/OFF magnet
The magnet seen in figure II.6 will stick the box to the yellow hook. Two small aluminum
supports, as seen in figure II.7 will help to easily center the magnet, and forbid the box from
falling on the rail track in case the magnet malfunctions.
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Fig.II.7. Magnet fixation
II.3. Configurations
II.3.1. TL-WA7510N
To access the TL-WA7510N configuration (out of the box), we must give the PC’s
network adapter a static IP, 192.168.1.100 / 255.255.255.0 is a good choice because the
access point is on the network 192.168.1.0. Now we can access the configuration page by
entering 192.168.1.254 in the browser. The TL-WA7510N must be configured as an access
point on the camera side with DHCP capability, so the small board computer can easily join
the network, without having to configure its network interface.
II.3.2. IP camera
Since the driver shouldn’t check the camera’s IP every time he runs the system, the
camera should be given a static IP, this way we can write a script to be run on the small board
computer immediately after boot, to show the camera’s video throughput.
II.4. Conclusion
After we finished the design of the camera side, we need to put a complete concept for
the locomotive side, with the electrical and mechanical designs along with the configurations
of the parts.
Notes: -refer to Annex B for details on the mechanical and electrical designs
-refer to Annex C for details on the configuration procedure
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Chapter III – Locomotive side design
III.1. Design overview
Fig.III.1. Design schematic-locomotive side
As seen in figure III.1, we will use an AC to DC converter that respects the EN50155
norm, which is the European standard for “Railway applications - Electronic equipment used
on rolling stock”, to provide 12 VDC to feed the access point’s PoE injector, the LCD screen
and the 12 to 5 VDC converter which will feed the Raspberry PI, the chosen small board
computer.
III.2. Smart LCD
Fig.III.2. LCD screen
19
The LCD screen seen in figure III.2, which was used in the analogue system, is powered
by 12 VDC. Its frame is made of metal and it is fixed in the locomotive using magnets. We
wanted to use the same LCD for this system.
Fig.III.3. Black box content
The idea is to make a sort of smart LCD, by adding a black box to it, which content can be seen
in figure III.3, where the user will only have to feed it power and connect the right cables to
get the video throughput on the screen, without having to configure anything. Since the LCD
screen had only a composite input, the chosen SBC must have an adapted output. Raspberry PI
model B was the best choice due to its low price, its capability to output on both composite and
HDMI connectors and to decode HD videos.
III.2.1. TEN 40-4812WIR
The voltage supply from the locomotive is a 36VAC - 16⅔ Hz. According to the
EN50155 norm [4], the voltage supply will vary from 70% to 125% the value of the nominal
voltage (36VAC in our case), that means from 25.2 V to 45 V. Using a full wave diode bridge
with a 10000µF smoothing capacitor, we will obtain an appropriate DC voltage for the Traco
power TEN 40-4812WIR DC-DC converter, which has an input of 18 to 75VDC, an output of
12VDC – 3.3A and it has an EN50155 approval.
III.2.2. TEN 5-1211
The TEN 5-1211 from Traco Power is a 12 to 5 VDC converter. It has an input marge
of 9 to 18 VDC and an output of 5 VDC-1A, enough to power the Raspberry PI which
consumes 700mA at maximum. We will use a NC push button to cut the power off the
Raspberry PI in case it froze.
20
III.2.3. Interior design
Fig.III.4. Black box interior design
From figure III.4, we can see that the 12 VDC output of the Traco Power will feed the
PoE injector via a DC jack. From it we will take 2 Ethernet cables: one connected to the LAN
port of the PoE injector, this will go to the Raspberry PI, and one connected to the PoE port,
this will go to the mounted connector. We will also provide power from the 36 to 12 VDC
converter to the 12 to 5 VDC converter. From it we will power the Raspberry PI via a micro
USB cable. Both the composite and the HDMI output of it will be provided outside the plastic
box via the appropriate connectors.
To make some sort of control over the components of the circuit, we will use a led on each of
the outputs to monitor the states of the converters. An illuminated switch will prove that the
box is provided with power, a red light will prove that 12 VDC is available and a green one
will prove that a 5 VDC is available.
The reason we are using different n-way connectors each time is so the user does not get
confused and plugs a false input into a connector, for example, this way we can prevent the
user from charging the battery of the OCH2 via the 36 VAC power provided from the
locomotive.
21
III.3. Configurations
III.3.1. TL-WA7510N
The access point should be configured in bridge mode on this side. This way, the video
signal data sent via Wi-Fi from the OCH2 box will be transferred to the Ethernet interface, and
then we can decode it using the Raspberry PI.
III.3.2. Raspberry PI
We used Omxplayer to decode the video stream. It is a video player specifically made
for the Raspberry PI’s hardware. The first stream test with the default settings gave a delay of
1 minute. By lowering the buffer size to 1MB, we obtained a delay of 20 seconds. This was
due to the fact that the player was decoding both audio and video streams, even though the
audio was muted from the camera’s configuration.
After an upgrade to the camera’s firmware, this issue was fixed. The camera stopped sending
audio stream, it was a bug in the old firmware. The delay became of 10 seconds.
The only solution was to lower the buffer size even more. The smallest value was 0.05 MB,
with it we obtained a delay of 1 second. By changing the configuration of the camera (different
frame rate, bit rate, video type), we were able to arrive to approximately a delay of 0.3 seconds.
Since the trains of Tridel do not transport the cargo at high speed, 0.3 seconds are acceptable
for this application. For the final product, we might need to change the SBC to a more powerful
one, like Intel nuc for example, to obtain a lower delay and approach real time video stream.
III.4. Conclusion
Now that we finished the design of the system, we will put the concept of an improved
one where the battery of the camera box will be powered by a motorized solar panel.
Notes: -refer to Annex B for the mechanical design
- refer to Annex C for details on the TL-WA7510N configuration
- refer to Annex D for details on the capacitor choice
- refer to Annex E for details on the Raspberry PI configuration
22
Chapter IV – Solar panel design
IV.1. Introduction
Solar trackers are devices used to orient photovoltaic panels, reflectors, lenses or other
optical devices toward the sun. Since the sun’s position in the sky changes with the seasons
and the time of day, trackers are used to align the collection system to maximize energy
production. Several factors must be considered when determining the use of trackers. Some of
these include: the solar technology being used, the amount of direct solar irradiation, and the
cost to install and maintain the trackers.
There are many types of solar trackers, of varying costs, sophistication, and performance. The
two basic categories of trackers, which can be seen in figure IV.1, are single axis and dual axis.
Fig.IV.1. Rotation axes of solar panels
IV.1.1. Single axis
Solar trackers can either have a horizontal or a vertical axis. The horizontal type is used
in tropical regions where the sun gets very high at noon, but the days are short. The vertical
type is used in high latitudes where the sun does not get very high, but summer days can be
very long.
IV.1.2. Dual axis
Solar trackers have both a horizontal and a vertical axis and thus they can track the sun's
apparent motion virtually anywhere. Many traditional solar PV applications employ two axis
trackers to position the solar panels perpendicular to the sun’s rays. This maximizes the total
power output by keeping the panels in direct sunlight for the maximum number of hours per
day.
23
IV.1.3. Energy generation comparison
Fig.IV.2. Power efficiency chart
As you can see from figure IV.2, the solar panels with dual axis trackers are much more
efficient than fixed ones. The single axis tracker is not very logical for our system because the
train can change its orientation in any moment, so the panel can’t be fixed along the east/west
axis all the time.
IV.2. Solar tracker
IV.2.1. Description
The system tracks the sun by relying on a set of sensors with a limited field of view. As
the sun moves, it begins to shade one or more sensors, which the system detects and activates
motors to move the device back into a position where all sensors are once again equally
illuminated.
Fig.IV.3. Solar tracker block diagram
24
Figure IV.3 shows the block diagram of the system, where the microcontroller will react on
the 2 stepper motors according to the input of the sensing circuits.
IV.2.2. Tracker Components
The main elements of a tracking system are as follows:
• Sun tracking algorithm: Some algorithms are purely mathematical based on astronomical
references while others utilize real-time light-intensity readings.
• Control unit: The control unit executes the sun tracking algorithm and coordinates the
movement of the positioning system.
• Positioning system: The positioning system moves the panel or reflector to face the sun at the
optimum angles. Some positioning systems are electrical and some are hydraulic.
• Drive mechanism/transmission: The drive mechanisms include linear actuators, linear drives,
hydraulic cylinders, swivel drives, worm gears, planetary gears, and threaded spindles.
• Sensing devices: For trackers that use light intensity in the tracking algorithm.
IV.3. Microcontroller choice- Arduino Nano
IV.3.1. Description
Fig.IV.4. Arduino pins
The Arduino Nano, seen in figure IV.7, is a small, complete, and breadboard-friendly
board based on the ATmega328 (Arduino Nano 3.0) orATmega168 (Arduino Nano 2.x). There
are many Arduino variations but this is the smallest in size and the cheapest in price. The reason
this microcontroller is the best choice is because it has a built in library for the stepper motors,
25
so it is very easy to control precisely the position of the solar panel, and it is cheap compared
to other solutions that offer the same capabilities.
IV.3.2. Power
The Arduino Nano can be powered via the Mini-B USB connection. In this conception,
we will use the Arduino breadboard just for design purposes. In the final product, an
ATmega328 should be used with the appropriate components as this lowers the power
consumption to as much as a factor of 1/9 [5]. The ATmega328 is also powered via a 5V source.
There are several ways to use the Arduino software to program the ATmega328 microcontroller
[6] [7]
. This is very helpful because it will make the control of the stepper motors much easier.
IV.4. Sensor design
The sensor is based on a photodiode. Its current output will arrive to approximately
1000 µA at a 10^4 luminance. By using the circuit seen in figure IV.4 which is a current to
voltage converter, we will translate the luminance to a voltage output between 0 and 5V, typical
for the Arduino’s ADC.
Fig.IV.5. Sensor circuit design
By using four of these sensors on each side of the panel, we can control its position on a 2 axis
level.
26
Fig.IV.6. Sensor fixation and protection
As seen in figure IV.5, these sensors will be put inside a PVC tube so we can limit their angle
of view. A glass cover should be used to make them weatherproof. Because the sun rays are
parallel, the sensors have to be fixed on each side of the panel in an inclined way.
Fig.IV.7. Sun rays hitting the solar panel
As an example, in figure IV.6, the output voltage of the left sensor will be higher than the right
one, and the microcontroller will know from the difference that it has to lower the panel’s left
side until the output of the two sensors become the same.
IV.5. Stepper motor
IV.5.1. Types of steppers
There are two basic types of steppers, bipolar and unipolar. The bipolar stepper has 4
wires. Unipolar steppers have 5, 6 or 8 wires. The Unipolar Stepper motor has 2 coils, simple
lengths of wound wire. The coils are identical and are not electrically connected. Each coil has
27
a center tap - a wire coming out from the coil that is midway in length between its two terminals.
The reason for this is to reverse the current.
The Bipolar Stepper motor is very similar except that the motor coils lack center taps. Because
of this, the bipolar motor requires a different type of controller, one that reverses the current
flow through the coils by alternating polarity of the terminals, giving us the name Bipolar. A
Bipolar motor is capable of higher torque as we can see from table IV.1 and figure IV.8, since
entire coils may be energized, not just half-coils, which is beneficial in our case (more torque
with the same motor weight). Where 4-wire steppers are strictly 'Bipolar', 5 and 6 wire motors
with center-taps can be used with the bipolar controller as parallel or series bipolar motors,
depending on the way the coils are joined.
Connections
Resistance
(Ohms)
Inductance
(mH)
Current
(A)
Voltage
(V)
Holding Torque
(oz-in)
Unipolar
Same as NamePlate Same as NamePlate Same as NamePlate
Same as
Same as NamePlate
NamePlate
Bipolar Series
NamePlate X 2
NamePlate X 0.707
NamePlate
NamePlate X 1.414
X 1.414
Bipolar Half Coil Same as NamePlate Same as NamePlate Same as NamePlate
Same as
Same as NamePlate
NamePlate
Bipolar Parallel
NamePlate X 0.5
NamePlate X 4
Same as NamePlate NamePlate X 1.414
NamePlate
NamePlate X 1.414
X 0.707
Table.IV.1. Comparison between stepper motors types
Fig.IV.8. Speed vs. torque chart
The H-bridge seen in figure IV.9, is used to reverse the current through the coil by closing the
appropriate switches - AD to flow one direction then BC to flow the opposite.
28
Fig.IV.9. H-Bridge used to control bipolar motors
IV.5.2. Bipolar motor control-SN754410
The SN754410 is a quadruple high-current half-H driver designed to provide
bidirectional drive currents up to 1 A at voltages from 4.5 V to 36 V. Drivers are enabled in
pairs with drivers 1 and 2 enabled by 1,2EN and drivers 3 and 4 enabled by 3,4EN. A separate
supply voltage (VCC1) is provided for the logic input circuits to minimize device power
dissipation. Supply voltage VCC2 is used for the output circuits. The SN754410 is designed
for operation from −40°C to 85°C.
IV.5.3. Motor and microcontroller interface
Fig.IV.10. SN754410 interface with the motor and the Arduino
In figure IV.10, we can see the connections between the H-bridge, the Arduino and the
motor. The connector at the OCH2 box is a 4-way one capable of providing up to 5A. To
recharge the 12V battery, we are only using 2 pins. We can use the other 2 to take power from
the battery to the motors and the microcontroller. This is essential to be able to catch the sun in
case the solar charger is not working anymore due to not enough power being produced (sun
was lost, rain,…).
29
IV.5.4. Motor ratings and fixation
Depending on the chosen gears that will rotate the panel around the two axis, the torque
of the motors must be chosen. The voltage rating of the motors must be of 12 V, in accordance
with the lithium battery.
The mechanical fixation of the motors with the gears could be similar to the one used with
satellite dishes, as seen in figure IV.11.
Fig.IV.11. Gears on a mechanical dish
IV.6. Tracker algorithm and block diagram
IV.6.1. Algorithm
Fig.IV.12. Tracker algorithm chart
30
The algorithm chart seen in figure IV.12 is as follows: the output of the four light
sensors, fixed at each side of the solar panel, will be connected to the Arduino’s analogue input.
The Arduino will then calculate the difference between them and move the solar panel
accordingly. For example if the north sensor has a higher voltage than the south one, this means
that the sun’s rays are coming from the north of the panel but are not perpendicular to it. We
then need to operate the motor connected to the north/south axis a number of steps proportional
to the difference in voltages between the sensors, to rotate the panel towards the north. If the
output of all the sensors is small, this means that the sun went down and that it’s time to return
to the initial position, where the panel is perpendicular to the solar rays at sun rise.
The sun moves one degree east to west every 4 minutes. An error of 5 degrees in “x” or “y”
represents a loss of 0.4% from the panels. But in our application, the train could change its
direction at any given moment. So the value of “y” should be made according to the train track
(straight, curvy,…).
To be able to track the sun in case of clouds, the value of the voltages to be considered zero
must be studied very carefully, because even if there are clouds in the sky, there is always a
bright point (the brightest cloud in this case), and voltages read during a cloudy day must be
differentiated from those read when the night comes.
IV.6.2. Block diagram
Fig.IV.13. Solar tracker block diagram
As seen in figure IV.13, the photodiode based sensors will be connected to the analogue
input of the microcontroller. The digital output of that last one will be used to control the Hbridge drivers of the bipolar stepper motors, which will move the panel either around the
north/south axis or the east/west one.
31
IV.7. Voltage regulator design
IV.7.1. Solar panel’s specifications










Product Name Lux.Pro DSP 20M
Dimensions (H x W x D) mm 468 x 350 x 25
Weight in kg 2.34
Cell type Mono
Cells per module 18 pcs.
Power max. 20W
Voltage max. 9.12 V
Current max. 2.25A
Open circuit voltage 10.94 V
Short circuit current 2.71 A
The solar panel is equipped with an aluminum frame and hail-resistant safety glass, as seen in
figure IV.14. On the back there is a waterproof junction box.
Fig.IV.14. Used solar panel
IV.7.2. Maximum Power Point
The solar cell V-I characteristic is nonlinear and varies with irradiation and temperature,
as seen if figure IV.15. In general, there is a unique point on the V-I or V-P curve, called the
Maximum Power Point (MPP), at which the entire PV system operates with maximum
efficiency and produces its maximum output power. The location of the MPP is not known, but
can be located, either through calculation models or by search algorithms. Therefore Maximum
Power Point Tracking (MPPT) techniques are needed to maintain the PV array’s operating
point at its MPP.
32
Fig.IV.15. Solar cell I-V curve in varying sunlight
The line that intersects the knee of the curves is where the maximum power point is located. A
device should be used to find this point in order to harvest the maximum power.
IV.7.3. Circuit design
Fig.IV.16. Charger circuit overview
The maximum power point tracker is bq24650, an IC from Texas instruments that is based on
a buck converter. The battery we used for the OCH2 is a 12 VDC one that charges at 12.6
VDC, so we need a boost converter to supply the right voltage to it. The bq24650 provides,as
seen in figure IV.16, via 2 connected LEDs to its output, a kind of a control signal over the
status of the charger (charge complete, charge in progress,…). From the battery we will use a
33
buck converter to provide a 5V supply to the Arduino. The reason we need this architecture is
because 5V batteries do not exist.
IV.7.4. BQ24650
The bq24650 is a highly integrated switch-mode battery charge controller. It provides
input voltage regulation, which reduces charge current when input voltage falls below a
programmed level. When the input is powered by a solar panel, the input regulation loop lowers
the charge current so that the solar panel can provide maximum power output.
The bq24650 supports a battery from 2.1V to 26V with VFB set to a 2.1V feedback reference.
The charge current is programmed by selecting an appropriate sense resistor.
The input of this IC will be 9.12V-2.25A, those are the specifications of the solar panel. The
output will be 5V-4A.
IV.7.5. TPS55340
The TPS55340 is a monolithic non-synchronous switching regulator with integrated
5A, 40V power switch. It can be configured in several standard switching-regulator topologies,
including boost, SEPIC and isolated flyback. The device has a wide input voltage range (2.9V
to 32V). The use of this device in our solar charger will be to boost the 6V output of the
bq24650 to a 12.6V, the ideal voltage to charge the battery.
IV.7.6. TPS84620
The TPS84620RUQ is an easy-to-use integrated power solution that combines a 6-A
DC/DC converter with power MOSFETs, an inductor, and passives into a low profile, BQFN
package. This total power solution allows as few as 3 external components and eliminates the
loop compensation and magnetics part selection process. With its efficiencies of up to 96%, its
wide-output voltage adjust of 1.2 V to 5.5 V, and its operating temperature range of –40°C to
85°C, it is a good choice to convert the 12VDC output of the battery to a 5VDC one to power
the Arduino.
IV.8. Conclusion
The design of the whole system is finished. Now we should run some tests to see if the
new system has ameliorated over the last one, and see which points in the current design need
to be further improved.
Note:-refer to Annex F for the electronic circuits of the solar design and their calculations
34
Chapter V – System test
V.1. Test 1
In this test, we tried to compare the range between the old analogue system and the new
digital system. The test went in the garage of the firm with the antennas facing each other
directly. The analogue system was able to transmit the image without any problems for
approximately 100 meters, but after that the signal was cut off. The digital one on the other
hand ran for a distance of approximately 400 meters, so there was a 4 times improvement over
the last system.
V.2. Test 2
This test went on the train used by Tridel. We did several tries with different antennas
positions. On the first try, the antennas were fixed as previewed in the design. The system ran
very well, the signal got cut off for less than 1 second, 2 times during the whole trip from the
yard to the factory. This trip takes approximately 11 minutes, so the performance of the system
is very acceptable. The magnet we bought was not efficient to hold the box to the yellow hook
so for the test, we used a silk band to fix it, as you can see from figure V.1.
Fig.V.1. Box fixed on the yellow hook during test
35
On the second try, we fixed the antenna under the yellow hook. The signal got cut off several
times due to the fact that the antennas are not facing each other’s directly this way, because of
the curvy route of the train.
V.3. Test conclusion
To fix the antennas the best possible way, they should be extended to the maximum,
away from the yellow hook on the camera side and the SBB cargo wagon on the locomotive
side. This way the antennas will have the best possibility to view each other. In the tunnel, we
don’t have this problem because of the strong reflection of the 5 GHz band on the walls.
For the camera configuration, the SSDR should be turned to a high level to obtain a clear picture
in the tunnel, because the lights in the tunnel, seen in figure V.2. will make the picture blurry
in night mode.
Fig.V.2. Tunnel used by Tridel
For the tests, the raspberry pi’s box was not finished so we used VLC player on a laptop to
decode the video stream. By changing the configurations of the camera, we clearly saw that the
mpeg configuration gave a lower delay than the h.264 one. It was almost without any delay
when the VLC player was configured with a low buffer size of 200ms.
36
Conclusion
During these 4 months, I was able to finish the complete design of the railway camera
system and to put the concept of a motorized solar panel to feed it. This project, Eyesrail_DIG,
will continue to develop with other students and technicians until it becomes a product ready
to be sold to the Swiss companies using SBB cargo wagons.
Since the test ran smoothly when the antennas were fixed as previewed, further development
of the product should be based on this report, especially since all the electrical and mechanical
designs, BOMs and configurations are detailed.
This project was a bit challenging but very interesting. It was a real engineering project that
gave me a lot of expertise in the field of systems design, both on the electrical and mechanical
level. I was also able to learn more about the solar panels and how they are controlled, and the
basics of socket programming.
In these 4 months, I have used a bit of all the things I have learned from my university, from
telecommunications to improve on the analogue system, to sensors design to use them on the
solar panel, to microcontroller architecture to choose the right microcontroller to control the
motors, to power electronics to choose the right converters,…
As for the Overo gumstix, it still needs a lot of work. The configurations of the program that
registers the images in case of motion needs to be changed, and the Wi-Fi needs to be fixed so
it can become a true autonomous camera.
Note:-refer to Annex I for the Overo gumstix part
37
Annex A- Materials comparison
A.1. Analogue Solution Tx/Rx products
TX Power
1w
1.5w
0.5w
na
na
na
2w
2.5w
3W
3w
0.1w
RX Power
Na
Na
Na
Na
Na
Na
Na
Na
Na
Na
-86dBm
Price
45
45
49
50
62
64
65
74
153
255
179
Description
2.4ghz 1w 4-ch
2.4GHz 1.5W 4-CH
2.4GHz 0.5W
2.4GHz 4-CH
2.4 GHz Wireless
2.4Ghz Wireless
2.4GHz Wireless Audio and Video
2.4GHz 2.5W 6-CH
2.4GHz 3W 6-CH
8CH Video Audio 2.4GHz 3W
1000 Foot Digital
Manufacturer
Bada
na
Bada
Pakite
Terk Technologies
Na
Na
bada
bada
SaferGuard
Na
Reference number
19828
20507
19761
E17762
LF-30S
AG29269
25582
19829
961019830
SPB0196G
PD24-D100
189
Compact Digital
Na
KW2400
429
LONG RANGE 3 MILE
WEATHERPROOF
2.4 GHz Wireless Digital Video
Sender
2.4GHz Digital Wireless
5.8GHz Wireless A/V STB
5.8GHz 1W Wireless Transmitter
5.8GHz Wireless A/V
5.8GHz Wireless AV Sender
Wireless 8-Channel Indoor
5.8GHz 400mw AV Wireless
5.8GHz Wireless 8-Channel
Indoor
Na
PD24-RSPL
RF-link
DAV-2450
-85dBm
-90dBm
Na
Na
Na
Na
-90dBm
-25-> -84dBm
Modulation
2.4GHz
2.4GHz
2.4GHz
2.4GHz
2.4GHz
2.4GHz
2.4GHz
2.4GHz
2.4GHz
2.4GHz
2.4GHz16QAM/QPSK/BPSK
2.4GHz-BPSK, QPSK, 16QAM
2.4GHz-QPSK
5.8GHz
5.8GHz
5.8GHz
5.8GHz
5.8GHz
5.8GHz
5.8GHz-FM
0.1w
-81dbm
0.2w
-85dBm
18dBm(0.06w)
-80dBm
0.01w
na
1w
na
na
na
0.4w
na
Rhinoco
Pakite
Na
Na
RF-link
RF-link
Na
RF-link
AVTXRX2.4
PAT-530
155954
AG29270
AVS-5811
AVS-5808-RX
RC305+TX5400
AVS-5808
0.5w
0.8w
1.5w
Na
Na
Na
900Mhz
900MHz
900MHz
149
189
219
900 MHZ 500MW
800MW 900 MHZ
Long Range 900 MHz 1.5 Watt
Na
Na
Na
PD9-500
PD9-800
PD9-1500
142
na
57
77
81
104
148
100
260
38
A.2. Digital solution Tx/Rx products
TX Power
-
RX Power
-
Modulation
-
Price
100->450
27dBm
25dBm
27dBm
29dBm
27dBm
26 dBm
17dBm
18dBm
29dBm
27dBm
-73->-95dBm
-75->-95dBm
Na
-73->-97dBm
Na
-67->-88dBm
-68->-87dBm
Na
-73->-97dBm
-74->-89dBm
2.4-5GHz
2.4GHz
2.4GHz
2.4GHz
2.4GHZ
2.4GHz
2.4GHz
2.4GHz
2.4GHz
2.4GHz
455
63
85
88
91
110
206
240
247
251
22-26dBm
15-20dBm
-74 -> -94 dBm
-72->-94dBm
2.4GHZ
2.4GHz
430
880
28dBm
27dBm
Na
Na
5GHZ
5GHZ
89
233
23-28dBm
21dBm
-73 -> -95dBm
-97dBm
5GHZ
900MHz
350
1400
Description
Cisco Small Business Wireless-G Exterior Access
Point
Dual Radio 802.11n Wireless Outdoor Access Point
Long-Range Wireless 2.4GHz Outdoor Bridge
Wireless-N Long Range AP(omni directional)
Long-Range Multiple Client Bridge/AP
Wireless-N Outdoor Client/Bridge/AP(directional)
N150 Wireless Outdoor PoE Access Point
Wireless 300N Outdoor PoE Access Point
Hi-Gain Outdoor Multifunction Access Point
Wireless-N Outdoor Access Point
14dBi High Power Wireless Outdoor PoE Access
Poin
Outdoor, Weatherproof, 3 Mile
Cisco Aironet 1300 Series Outdoor Access
Point/Bridge
Long Range 802.11n Outdoor Bridge AP
12dBi N300 Wireless 5GHz Outdoor PoE Access
Point
Outdoor,weather proof
Video Surveillance Transmitter, 900Mhz
Manufatrurer
Cisco
Reference number
WAP series(see PDF)
EnGenius
EnGenius
EnGenius
EnGenius
EnGenius
Trendnet
Intellinet network solutions
Hawking technology
EnGenius
Trendnet
ENH700EXT
ENS200
ENH200EXT
ENH202
ENH200
TEW-715APO
524711
HOWABN1
ENH210EXT
TEW-455APBO
cctvcamerapros
Cisco
EnGenius
Trendnet
WIFI-NAN72B
AIR-BR1310G-AK9-R
ENH500
TEW-676APBO
cctvcamerapros
cctvcamerapros
WIFI-EH9500
WIFI-900XTRP
39
A.3. IP Cameras
Resolution
(max)
640 x 480
Frame rate (max)
Dimensions(mm)
100
640 x 480
1280 x 800
1280 x 1024
1280 x 1024
Power
consumption
12 VDC Max
3.3W
12 VDC Max 5W
12 VDC Max 6W
12 VDC Max 3.7
W
12 VDC Max
5.6W
12 VDC 8.6W
12 VDC Max 4W
12 VDC 3.3W
12 VDC Max 4W
1600 x 1200
12 VDC 8w max
640 x 480
640 x 480
640 x 480
640 x 480
Price
Manufacturer
109.7 x 44 x 29
Operating
temperature(°C)
-10 -> 50
800
Basler
Reference
number
BIP2-640c-dn
30
25
30
85 (φ) x 265
155 x 82 x 80
74.3 x 54.5 x 114.4
-30 -> 50
-5 -> 45
-10°C ~ +50°C
350
71
325
Zavio
TENVIS
Samsung
F731E
IP602W
SNB-1001P
30
Ø86.8 x 304.6
-10 -> 50
400
Samsung
SNO-1080R
30
30
30
30
188.5 x 91.6 x 85.2
Ø: 60 x 170
67 x 55 x 129.5
80 x 166.8 x 62
-20 -> 50
-20 -> 50
0 -> 50
0 -> 40
340
250
420
350
Ganzg
Vivotek
ACTI
D-link
ZN-B1A
IP8332
ACM-5611
DCS-3110
30
72x 154 x 62
0 -> 50
400
Vivotek
IP7161
40
A.4. LCD
Size
(inches)
17
Power
Input
Price
Description
Manufacturer
Ref. number
VGA
Dimensions
(cm)
36.6x30.2x5.8
100-240V
43
Samsung
LS17HALJBY
AC 100-240V
VGA
37.8x14.2x27.9
60
Hannspree
HL161ABB
20
19
26W
16.5W
VGA-DVI
VGA
Na
Na
90
92
HP
Acer
W2072a
ET.CV3WP.E05
17
100V-240V13.9W
VGA
36.8x37.5x16
125
Acer
V173DJb
21.5
20
36W
30W
HDMI-DVI
HDMI-VGA
Na
47.5x30x5.3
145
160
Asus
Samsung
VS229H-P
S20B350H
17
100 - 240v-20 W
VGA-DVI
37x31.4x6.8
160
Samsung
B1740R
15
VGA
33.4x6x29.6
180
Planar
PL-PL1500M
21.5
AC 100240V;25W
30w
HDMI-VGA
50.8x32x5.3
190
Samsung
S22B350H
17
17
Na
Na
HDMI-VGA
HDMI-VGA
Na
38.5x6.5x33.5
200
226
Samsung SyncMaster 740N LCD Monitor
(Refurbished)
HannsG 16" Wide 1366x768 LED Monitor,
VGA
LED-Backlit LCD Monitor, Black
50,000:1 5ms VGA LCD Monitor (Black) ET.CV3WP.E05
LCD Monitor (EPEAT) with 1280x1024
Resolution, 20,000:1 Dynamic Contrast
Ratio, 250cd/m2 Brightness
Widescreen LED Backlit LCD Display
Widescreen LED Backlit Monitor - 1600 x
900, 16:9,
LCD Monitor - 5ms - 1280 x 1024 - 16.7
Million Colors - 250Nit - 1000:1
15 inch 700:1 8ms VGA LCD Monitor, w/
Speaker (Black) - 997-5905-00
Class Widescreen LED Backlit Monitor 1920
Eversun SH17 CCTV LCD Monitor
1280X1024, SXGA, 4:3, 250CD,
15.6
Eversun
Everfocus
E159-1014
EN7517HDMIA
41
A.5. M12 PoE Switch
Number of
POE ports
4
Total number
of ports
8
Max Power (per
port)
15
Power supply
Dimensions (cm)
Price
Description
Manufacturer
Ref. number
24-48VDC
9.2 x 18 x 4.2
735
Advantech
EKI-6528TPI-AE
4
8
15
48 VDC/1.6A
na
899
moxa
TN-5308-4PoE-48T
8
8
30
24VDC
19.2x14.5x12
1700
Korenix
JetNet 6810G-M12
8
12
30.8(61.6 W ±7%
distributed on all
PoE ports)
14.2x10x11
2628
Westermo
Viper-212-P8
ordered
Ordered
Ordered
48 to 110 VDC
1.7 A @ 48 V,
Max 0.74 A @
110 V
Ordered
EN50155 8xM12
Unmanaged
Switch w/ PoE
Unmanaged
Ethernet switch
with 4
10/100BaseT(X)
ports and 4 PoE
ports
8+2G Managed
PoE Switch
managed EN
50155 PoE
Routing Switch
na
na
Kyland
SICOM5208R
2
8
Na
24/110 VDC
22x13x7
na
men
06RS02
8
10
15
48VDC
21.7x14x6.6
na
Ordered with
respect to need
(port number, poe
ports, unmanaged,
…)
RS2 - IP67
Industrial Ethernet
Managed Industrial
Switch w/8 PoE
Injectors
Lantech
IPES-2208-M12-65
42
A.6. RJ45 PoE Switch
Number
of POE
ports
4
Total
number
of ports
8
Max Power
(per port)
Power supply
Dimensions
(cm)
Price
Description
Manufacturer
Ref. number
15
7.5V DC/1A
23.5 x 10 x 2.7
54
NETGEAR
FS108P
4
8
15
18.2x26x4
56
ZyXEL
ES1100-8P
4
8
15
100240VAC/1.5A
48V/0.8A
17.1 x 9.8 x 2.9
60
TRENDnet
TPE-S44
4
8
15
48V DC/1.45A
17x10x2.8
86
D-Link
DES-1008PA
4
4
8
8
15
15
12VDC/1.0A
48VAC/1.875A
16x12.8x3
12x19x3.8
100
116
Cisco
Fortinet
SG100D-08P-NA
FS-80-POE-US
4
4
8
5
35
35
21x10.4x2.8
15.9 x 11.8 x 4
140
170
Zyxel
Tycon
GS1100-8HP
TP-SW5G-24
8
8
35
26.4x16x4.3
221
TPE-T80
5
8
15
35
9.7x3.8x9
28x18.5x4.3
279
316
TPE T80 PoE+ Switch Switch
- 8 ports
Industrial PoE Ethernet
8-port Gigabit Poe Plus
Switch
TRENDnet
4
8
120-230 VAC
1036VDC/90W
120-230
VAC/250W
48VDC/2A
110-220 VAC
8 Port 10/100 Desktop Switch
with 4 Port PoE Switch
8-Port ES1100-8P 10/100 PoE
Switch
8-Port 10/100Mbps PoE
Switch
8-Port Metal Desktop Switch
with 4 PoE Ports
Unmanaged Switch SF
FortiSwitch 80-POE Gigabit
Ethernet
Switch - 8 ports - unmanaged
802.3af PoE Gigabit Switch
N-tron
Cp tech
105TX-POE
GEP0822
43
A.7. Rugged industrial displays
Size(inch)
10.1
OS
Windows 7 Pro
Dimensions(cm)
26.3x17.1x3.7
Power supply
12~24V DC - 25W
Connector
RJ-45
Price
na
10.4
10.4
Windows 7 Pro
Windows XP
Embedded
28.5x24x7
22x31x9
12V DC/24V DC-10W
24VDC/ 110VDC-20W
na
M12-RJ45
2295
na
10.4
Windows XP
Embedded
22x31x9
24VDC/ 110VDC-20W
M12-RJ45
na
10.4
10.4
12.1
Windows 7 Pro
na
Windows 7 Pro
28.6x25.4x8.4
33.9x25.6x7.2
33x25.4x8.4
50W typ-80W max
9 to 36 V DC-26 W
50W typ-80W max
na
RJ45
na
na
na
na
Description
10.1" Panel PC-touch
screen-POE
Waterproof LCD-PC
Human Machine
Interface Intel® Atom
based with 32 Hardkeys
Human Machine
Interface Intel® Atom
based with Touch
10" smart display
10.4" Marine Panel PC
12" smart display
Manufacturer
Winmate
Small PC
Kontron
Ref. number
W10ID3S-PCH1PoE
SDC100
HMITR-104-AKT1-24
Kontron
HMITR-104-ATT1-24
Barco
Winmate
Barco
SV-126
R10A83S-MRM2
SV-231
44
A.8. SBC (Single Board Computer)
45
46
47
48
49
50
51
52
53
Annex B-Mechanical and electrical design
B.1. Antenna fixation - camera side
This mount will be fixed on the OCH2 in a sandwich way, to prevent the user from opening
the camera enclosure. The two U-supports are fixed together using two 18.5 bars. On top of one
of the U- supports, the antenna support will be fixed to which the antenna holder is screwed. The
access point has two holes specially made so it can easily be fixed with the plastic straps that came
with it. On the bottom of the U-shaped support, two small U-supports will be screwed.
Fig.B.1. 3D view of the antenna
Cutting the edge of the access point holder where the plastic straps will take place, will make it
hard for the access point to move around.
Fig.B.2. Access point fixation with plastic straps
54
B.2. Camera fixation
The standard camera mount is a ¼-20 screw. Samsung’s SNB-1001P comes with a thread
for this screw on its lower end.
Fig.B.3. Camera lower view
Fig.B.4. ¼-20 screw
The OCH2 camera housing comes with a plastic plate specially made to fix cameras on it. By
screwing the camera with a ¼-20 screw and fixing it with 2 plastic straps, the camera will be fixed
on the plate robustly.
Fig.B.5. Plastic plate
55
B.3. Battery and PoE INJECTOR fixation
B.3.1. Description
The available space in OCH2 is 30x10x8 cm. The camera with the objective will take a
space of 16.04 cm so 13.96 cm are available. By designing a metallic plate of 13.3x8 cm with the
appropriate fixation, we can put the battery and PoE on top of each other:
0.3(metallic plate) +4(battery) +0.3(U-support) +2.1(PoE injector) =6.7 < 8 cm
This plate will be used to hold the battery and the PoE. It has 8x0.3cm holes where M3 screws will
be used to fix the U-supports on the plate, and the plate on the OCH2, 2 long holes to regulate the
position of the battery. The battery will be fixed in place due to the M4 hexagon nuts.
Fig.B.6. 3D view of the battery and PoE fixation
B.3.2. Battery’s dimensions
56
B.3.3. PoE injector’s dimensions
B.3.4. Battery plate
This plate will be used to hold the battery and the PoE. It has 8x0.3cm holes where M3
screws will be used to fix the U-supports on the plate, and the plate on the OCH2, 2 long holes to
regulate the position of the battery. The battery will be fixed in place due to the M4 hexagon
nuts.
Fig.B.7. Metallic plate dimensions
57
Fig.B.8. Metallic plate 3D view
B.3.5. Battery holder
Fig.B.9. Battery holder 3D view
58
Fig.B.10. Battery holder top view
B.3.6. Battery and PoE injector assembly
Here we see the complete design with the battery (blue box) and Poe injector (green box).
We need one metallic plate and 2 U-supports.
Fig.B.11. System assembly method
59
1. Place the battery on the plate
2. Fix the battery holder with 4 M3 screws
3. Regulate the battery position and fix it with 2 M4 screws and nuts
4. Fix the PoE injector with 2 M3 screws
Quantity
2
2
2
4
2
1
Description
M4 nut
M4 6mm screws
M3 4mm screws
M3 6mm screws
Battery holder
Battery plate
Table B.1. Material quantities needed for the battery and PoE support
B.4. Antenna fixation
B.4.1. 18.5 bar
This bar will be used to hold the 2 U-supports and the 2 small U-supports together. For
this purpose, two 3 mm holes will be cut on each side.
Fig.B.12. Side view
Fig.B.13. Top view
60
Fig.B.14. 3D view
B.4.2. U-support
This support will be used to fix the system on the OCH2 and to hold the access point
support. For this purpose, three 3 mm holes will be cut on each side.
Fig.B.15. Side view
Fig.B.16. Top view
61
Fig.B.17. 3D view
B.4.3. Small U-support
This support will be used to fix the mount on the OCH2.
Fig.B.18. Holes type
Fig.B.19. Top view
62
Fig.B.20. Side view
B.4.4. Antenna support
The part will be used to hold the antenna holder to the U-support with a 3 mm screw and
nut. Between these 2 parts we will use a metallic circle to prevent the deformation of the parts.
Fig.B.21. 3D view
B.4.5. Antenna holder
On this part, the access point will be fixed with the plastic straps. The 135 angle will allow
the antenna to be held vertically for maximum signal (since the antennas are directional).
63
Fig.B.22. Lower part
Fig.B.23. Upper part
Fig.B.24. 3D view
64
Quantity
8
1
1
1
1
4
2
2
2
Description
M3 8mm
M3 16mm
M3 nut
Antenna holder
Antenna support
18.5 bar
U-support
Small U-support
Plastic straps
Table B.2. Material quantities needed for the antenna support
B.5. Mechanical design-locomotive side
B.5.1. Box design
Fig.B.25. Black box
On side 1 we will fix the RJ45 feedthrough connector, the illuminated switch and the 5-way plug.
Fig.B.26. Representation of side 1
On side 2 we will fix the composite and the HDMI connectors to connect the Raspberry PI’s video
output to the LCD display. A 2-way connector connected to the 12 VDC power supply will be
65
used to feed the LCD display. In case the Raspberry PI froze, the NC push button will fix this
problem by cutting off the 5 VDC power from the USB cable.
On side 3 we will fix 2 led lights connected to the 5VDC and 12 VDC output to provide power a
control signal in case the converters broke.
B.5.2. Box fixation
The LCD screen currently used has a magnet on its back, fixed to it via an M5 screw and
a nut. By cutting a 5mm hole on the plastic box and using this screw, and by adding two 3mm
ones, the box will be fixed robustly on the metallic support of the LCD screen.
66
Fig.B.29. Box interior view
Fig.B.30. Top view
Using the above dimensions, we will get a 9.75 cm space between the LCD screen and the plastic
box, enough to connect the cables and press the push button in case the Raspberry PI froze.
B.5.3. TL-WA7510N fixation
The antenna will be fixed on the SBB cargo wagon using a strong magnet. The antenna has
to be straight, directly facing the one of the camera. Like on the camera side, we will use plastic
bands to fix it on the aluminum bar, which has holes to forbid it from slipping.
Fig.B.31. TL-WA7510N fixation on the locomotive side
67
B.6. Electrical design – Camera side
B.6.1. Cable section calculation
The max current that will be drawn from the battery on a single cable is 2A, it is the current
used to charge the battery from the 2A DC charger. Using a DC cable section calculator [3], for a
12VDC-2A, with an acceptable loss of 1%, at a distance of 20 cm, 0.5 mm2 cables can be used. So
inside the camera box, 0.5mm2 cables will be used to feed the PoE injector, the camera, and to
charge the battery.
B.6.2. Electrical wires connection
Fig.B.32. Wires design overview
The switch, 4-way connector and fuse housing must be IP67 protected, which means
against dust and water, because they are exposed to open air.
The 4-way connector, with a protection cover, is an industrial one capable of resisting shocks and
vibrations. The reason we need a 4-way connector and not a 2-way is to implement a motorized
solar panel in a future design (refer to chapter IV).
The chosen switch is IP67 protected due to a protection cap. On one end of it, we will solder the 2
cables coming from the battery, on the other end, we will have 4 separate cables, 2 for the PoE
injector with a DC jack at the end, and 2 for the camera.
The PCB between the battery and the connector is formed of a diode bridge rectifier IC with a 10A
slow time fuse. The fuse will protect the battery in case of a short circuit, and the diode bridge will
protect it in case the polarization got inversed.
68
To protect the parts in case of a short circuit, we will use a fuse housing where a 5A time delayed
fuse will be used, and connect the positive cable to it. On the other end, we will solder 2 cables,
one to feed the PoE injector and the other to feed the camera.
B.6.3. Ethernet wires connection
OCH2 has a hole on its floor to take the cables outside. The PoE cable that must be led to
the antenna will be taken through this hole. A small LAN cable will connect the camera to the
LAN port of the PoE injector.
Fig.B.33. Interior Ethernet interface
Fig.B.34. Outdoor Ethernet interface
69
Annex C-Configurations
C.1. TL-WA7510N configurations
C.1.1. Static IP
To access the TL-WA7510N configuration (out of the box), we must give the PC’s network
adapter a static IP. Connect one end of an Ethernet cable to the POE port of the provided Power
Injector and the other end of the Ethernet cable to the LAN port of the TL-WA7510N. Then,
connect the LAN port of the Power Injector to a PC using another Ethernet cable. Finally, plug the
provided power adapter into the DC jack on the Power Injector, and the other end to a standard
electrical wall socket.
For Windows 7 OS
1.
2.
3.
4.
5.
6.
Go to Start > Settings > Control Panel
Click View network status and tasks
Click Change adapter settings
Right-click Local Area Connection
Click Properties
Double-click Internet Protocol Version 4 (TCP/IPv4)
7. Select Use the following IP address
8. Enter 192.168.1.100 into the IP address field, 255.255.255.0 into the Subnet mask field,
leave the DNS field empty
70
9. Click OK
Now we can access the configuration page by entering 192.168.1.254 in the browser
The login and password are both “admin”
C.1.2. TL-WA7510N camera side configuration
The TL-WA7510N must be configured as an access point with DHCP capability on this side:
1. Select quick setup
2. Click Next
3. Select Standard AP
4. Enter a unique and easy-to-remember name for your wireless network.
71
5. Select Switzerland from the drop-down list
6. Click Next and then finish
7. Select DHCP > DHCP Settings and switch DHCP Server to enable
72
C.1.3. TL-WA7510N locomotive side configuration
The TL-WA7510N must be configured as an access point with DHCP capability on this side:
1. Connect your computer to a AP with the hard wired connection, and then log into the
Web-based Interface by entering the IP address 192.168.1.254 into the Web Browser.
2. Change the LAN IP address of the access point to avoid IP conflict. After changing the IP
address of your access point, you need re-log into it by using the new IP address.
3. Configure your Access Point to Point to Point Bridge mode.
3. a. Click on Wireless ->Basic Settings on the left menu, change the channel to a fixed one.
3. b. Click Wireless -> Wireless Mode on the left, select Bridge (Point to Point).
w
w
3. c. Press Survey or Search button on the bottom, then an AP list will be displayed. Locate
the BSSID (MAC address) of the other access point, remember the Channel->
Click Connect.
73
3. d. Then you will see the MAC addresses of the other access point displayed in the
w
MAC of AP boxes.
3. e. Click on save button to save the settings.
4. Go to System Tools-Reboot to reboot the device.
C.2. Camera’s static IP configuration
Run <IP Installer_v2.XX.exe> to display the camera search list. At the initial startup,
both [Auto Set] and [Manual Set] will be grayed out.
1. Select a camera in the search list. Check the MAC address of the camera on the camera’s
label.
74
Both the [Auto Set] and [Manual Set] buttons will be activated.
2. Click [Manual Set]. The Manual Setting dialog appears. The default values of <IP Address>,
<Subnet Mask>, <Gateway>, <HTTP Port> and <VNP Port> of the camera will be displayed.
3. In the <Address> pane, provide the necessary information.
MAC (Ethernet) Address: The MAC address imprinted on the camera label is automatically
displayed and requires no user setting.
4. In the <Port> pane, provide necessary information.
HTTP Port: Used to access the camera using the Internet browser, defaulted to 80.
VNP Port: Used to control the video signal transfer, defaulted to 4520.
5. Enter the password of “admin” account, which was used to access the camera. The default
password is “4321”.
6. Click [OK]. Manual network setup will be completed.
75
Annex D-Capacitor choice
As there will always be some ripple on the output of a rectifier using a smoothing capacitor
circuit , it is necessary to be able to estimate the approximate value. Over-specifying a capacitor
too much will add extra cost, size and weight - under-specifying it will lead to poor performance.
[9]
Fig.D.1. Peak to peak ripple for smoothed diode rectifier circuit
The diagram above shows the ripple for a full wave rectifier with capacitor smoothing. If a half
wave rectifier was used, then half the peaks would be missing and the ripple would be
approximately twice the voltage.
For cases where the ripple is small compared to the supply voltage - which is almost always the
case - it is possible to calculate the ripple from a knowledge of the circuit conditions:
Full wave rectifier
∆𝑉 =
𝑰𝑙𝑜𝑎𝑑
𝟐∗𝒇∗𝑪
Half wave rectifier
∆𝑉 =
𝑰𝑙𝑜𝑎𝑑
𝒇∗𝑪
These equations provide more than sufficient accuracy. Although the capacitor discharge for a
purely resistive load is exponential, the inaccuracy introduced by the linear approximation is very
small for low values of ripple.
It is also worth remembering that the input to a voltage regulator is not a purely resistive load but
a constant current load. Finally, the tolerances of electrolytic capacitors used for rectifier
smoothing circuits are large - ±20% at the very best, and this will mask any inaccuracies introduced
by the assumptions in the equations.
The parts that will be fed from the 12 VDC converter are raspberry PI and TP-link antenna’s PoE
injector. The raspberry PI consumes maximum 700 mA at 5 VDC and the antenna consumes 670
mA at 12 VDC. So the maximum current that will be taken from the converter at 12 VDC will be:
76
670 +
700 ∗ 5
= 670 + 292 = 962 𝑚𝐴
12
At the input of the Traco power converter, at 36VDC, the current drained from the source will be:
12 ∗ 962
= 321𝑚𝐴
36
Assuming a 10% error margin, the approximate value of Iload will be
321 ∗ 110% = 353𝑚𝐴
With a ripple voltage of 1V at 36 VDC, with a full wave rectifier, the appropriate capacitance
value will be:
𝐶=
𝐼𝑙𝑜𝑎𝑑
0.353
=
= 0.01𝐹
2 ∗ 𝑓 ∗ ∆𝑉 2 ∗ 16.7 ∗ 1
So a 10 000 µF capacitor will be enough to smooth the rectifier’s output.
77
Annex E-Raspberry PI configuration
E.1. OS Installation [10]
1. Download Raspbian “wheezy” from http://www.raspberrypi.org/downloads
2. Extract the image file of wheezy from the downloaded .zip file.
3. Insert the SD card into your SD card reader and check what drive letter it was assigned.
You can easily see the drive letter (for example G:) by looking in the left column of
Windows Explorer. If the card is not new, you should format it and make sure there is
only one partition (FAT32 is a good choice).
4. Download the Win32DiskImager utility from https://launchpad.net/win32-image-writer
5. Extract the executable from the zip file and run the Win32DiskImager utility. You should
run the utility as Administrator.
6. Select the wheezy image file you extracted earlier
7. Select the drive letter of the SD card in the device box.
8. Click Write and wait for the write to complete.
9. Exit the imager and eject the SD card.
78
10. Insert the card in the Raspberry Pi, power it on, and it should boot up.
The first time you boot the Raspberry Pi you'll see a configuration tool called "raspi-config." (If
you ever need to revisit this configuration screen again, you can always call the "raspi-config"
command from the terminal of your Pi.). You'll need to change a few options.
First off, we need to select "expand_rootfs". What this does is expand the installed image to use
the maximum available size of your SD card. If you are using a larger card (16GB for example),
you'll definitely want to make sure you can use the full capacity, since the install image is only
about 2GB.
Highlight that "expand_rootfs" option and press Enter. You'll then see the confirmation below, at
which point pressing Enter will take you back to the main raspi-config screen.
79
Back at the main setup, you can safely ignore the remaining options for now and select "Finish."
You'll be prompted to reboot to make changes, do so. Once your system is back online, you'll get
a login prompt like so:
Your login is "pi" and the password will be “raspberry”
Now that you've logged in to Raspberry Pi, the first thing you want to do is type "startx" to get
your GUI environment loaded.
E.2. Streaming from the Samsung camera
URLs for Samsung SNB-1001 need to have credentials (the IP camera login name and password)
passed through in the URL like: rtsp://USERNAME:PASSWORD@IPADDRESS:PORT/
The default login and password are “admin” and “4321” respectively. The port used by the IP
camera for RTSP streams is 3000.
So to stream using Omxplayer, we should execute the following command:
omxplayer rtsp:// admin:4321@IPADDRESS:3000/
where IPADDRESS is replaced with the camera’s IP.
80
Annex F-Electronic circuits
F.1. Solar tracker
81
F.2. Solar charger
F.2.1. BQ24650
Battery voltage regulation
The bq24650 uses a high accuracy voltage regulator for the charging voltage. The charge
voltage is programmed via a resistor divider from the battery to ground, with the midpoint tied to
the VFB pin. The voltage at the VFB pin is regulated to 2.1V, giving the following equation for
the regulation voltage:
𝑅2
𝑉𝐵𝐴𝑇 = 2.1𝑉 ∗ [1 + ](1)
𝑅1
Where R2 is connected from VFB to the battery and R1 is connected from VFB to GND. By
choosing R2=100kΩ, we can calculate the value of R1
100
(1) 5𝑉 = 2.1𝑉 ∗ [1 + 𝑅 ] → 𝑅1 = 72.4𝑘Ω
1
The closest standard value [11] is 71.5kΩ.
Battery current regulation
Battery current is sensed by resistor RSR connected between SRP and SRN. The full-scale
differential voltage between SRP and SRN is fixed at 40mV. The value of RSR is calculated using
eq.2.
40 𝑚𝑉
𝐼𝐶𝐻𝐴𝑅𝐺𝐸 =
(2)
𝑅𝑆𝑅
The charging current we want is 4A, so RSR should be 10mΩ.
Converter operation
The synchronous buck PWM converter uses a fixed frequency voltage mode with feedforward control scheme. A type III compensation network allows using ceramic capacitors at the
output of the converter. The compensation input stage is connected internally between the
feedback output (FBO) and the error amplifier input (EAI). The feedback compensation stage is
connected between the error amplifier input (EAI) and error amplifier output (EAO). The LC
output filter must be selected to give a resonant frequency of 12 kHz – 17 kHz for the bq24650,
where resonant frequency, fo, is given by:
1
𝑓0 =
2𝜋√𝐿0 𝐶0
By using the below table, we can find that Lo=6.8µH and Co=20µF are the best values for the
design. We will use two 10µF capacitors in parallel which will give an equivalent 20µf
capacitance, because 20µf is not a standard value [12].
82
Charge Current
Output Inductor
Lo
Output Capacitor
Co
Sense Resistor
1A
15µH
2A
10µH
4A
6.8µH
8A
3.3µH
10µF
15µF
20µF
40µF
40mΩ
20mΩ
10mΩ
5mΩ
Table F.1. Typical Inductor, Capacitor, and Sense Resistor Values as a function of charge current
Inductor selection
The bq24650 has a 600-kHz switching frequency to allow the use of small inductor and
capacitor values.
Inductor saturation current should be higher than the charging current (ICHG) plus half the ripple
current (IRIPPLE)
𝐼
𝐼𝑆𝐴𝑇 ≥ 𝐼𝐶𝐻𝐺 + 𝑅𝐼𝑃𝑃𝐿𝐸
(4)
2
Inductor ripple current depends on input voltage (VIN), duty cycle (D = VOUT/VIN), switching
frequency (fs), and inductance (L) according to eq.5.
𝑉𝐼𝑁 ∗ 𝐷 ∗ (1 − 𝐷)
𝐼𝑅𝐼𝑃𝑃𝐿𝐸 =
(5)
𝑓𝑠 ∗ 𝐿
9.12∗0.55∗(1−0.55)
(5) 𝐼𝑅𝐼𝑃𝑃𝐿𝐸 = 600 000∗6.8∗10−6 = 0.55𝐴
0.55
(4) 𝐼𝑆𝐴𝑇 ≥ 4 + 2 = 4.275𝐴
So we should choose a 6.8µH inductor [13] having a saturation current rating higher than 4.275A
and supports a current of 4A.
Input over-voltage protection (acov)
ACOV provides protection to prevent system damage due to high input voltage. Once the
adapter voltage reaches the ACOV threshold, charge is disabled.
Input under-voltage lock out (uvlo)
The system must have a minimum VCC voltage to allow proper operation. This VCC
voltage could come from either input adapter or battery, since a conduction path exists from the
battery to VCC through the high-side NMOS body diode. When VCC is below the UVLO
threshold, all circuits on the IC, including VREF LDO, are disabled.
Battery over-voltage protection
The converter does not allow the high-side FET to turn on until the BAT voltage goes
below 102% of the regulation voltage. This allows one-cycle response to an over-voltage condition
– such as occurs when the load is removed or the battery is disconnected. A current sink from SRP
to GND is on to discharge the stored energy on the output capacitors.
83
Thermal shutdown protection
The QFN package has low thermal impedance, which provides good thermal conduction
from the silicon to the ambient, to keep junction temperatures low. As an added level of protection,
the charger converter turns off and self-protects whenever the junction temperature exceeds the
TSHUT threshold of 145°C. The charger stays off until the junction temperature falls below
130°C.
Temperature qualification
The controller continuously monitors battery temperature by measuring the voltage
between the TS pin and GND. A negative temperature coefficient thermistor (NTC) and an
external voltage divider typically develop this voltage. The controller compares this voltage
against its internal thresholds to determine if charging is allowed.
To initiate a charge cycle, the battery temperature must be within the VLTF to VHTF thresholds.
If battery temperature is outside of this range, the controller suspends charge and waits until the
battery temperature is within the VLTF to VHTF range. During the charge cycle the battery
temperature must be within the VLTF to VTCO thresholds. If battery temperature is outside of
this range, the controller suspends charge and waits until the battery temperature is within the
VLTF to VHTF range. The controller suspends charge by turning off the PWM charge FETs.
Texas instruments suggests to use a 103AT NTC on the battery pack for this purpose.
The values of RT1 and RT2 can be found using the spreadsheet found at ti.com.
Charge status outputs
The open-drain STAT1 and STAT2 outputs indicate various charger operations as listed in
the table below. These status pins can be used to drive LEDs or communicate with the host
processor. Note that OFF indicates that the open-drain transistor is turned off.
84
Table F.2. Charge status in function of LEDs on stat pins
Input capacitor
A low ESR ceramic capacitor such as X7R or X5R is preferred for the input decoupling
capacitor and should be placed as close as possible to the drain of the high-side MOSFET and
source of the low-side MOSFET. The voltage rating of the capacitor must be higher than the
normal input voltage level, which is 9,12V in our case.
Input filter design
During adapter hot plug-in, the parasitic inductance and the input capacitor from the
adapter cable form a second order system. The voltage spike at the VCC pin may be beyond the
IC maximum voltage rating and damage the IC. A cost effective and small size solution is shown
in the figure below. R1 and C1 are composed of a damping RC network to damp the hot plug-in
oscillation. As a result, the over-voltage spike is limited to a safe level. D1 is used for reverse
voltage protection for the VCC pin. C2 is the VCC pin decoupling capacitor and it should be placed
as close as possible to the VCC pin. R2 and C2 form a damping RC network to further protect the
IC from high voltage spike. The C2 value should be less than the C1 value so R1 can dominant the
equivalent ESR value to get enough damping effect for hot plug-in.
Values chosen for this design are R1=2Ω R2=20Ω C1=2.2µF and C2=0.47µF.
MPPT temperature compensation
A typical solar panel comprises of a lot of cells in a series connection, and each cell is a
forward-biased p-n junction. So, the open-circuit voltage (VOC) of a solar cell has a temperature
coefficient that is similar to a common p-n diode, or about –2mV/°C. A crystalline solar panel
specification always provides both open-circuit voltage VOC and peak power point voltage VMP.
The bq24650 employs a feedback network to the MPPSET pin to program the input regulation
voltage. Because the temperature characteristic for a typical solar panel VMP voltage is almost
linear, a simple solution for tracking this characteristic can be implemented by using an LM234 3-
85
terminal current source, which can create an easily programmable, linear temperature dependent
current to compensate the negative temperature coefficient of the solar panel output voltage.
From the solar panel specifications, we can find that VMP(25ºC)=9.12V and that this panel is made
of 18 cells. By choosing RSET=1kΩ, we can calculate the values of R3 and R4 using the following
equations:
2𝑚𝑉 ∗ 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑠𝑜𝑙𝑎𝑟 𝑐𝑒𝑙𝑙𝑠 𝑖𝑛 𝑠𝑒𝑟𝑖𝑒𝑠
𝑅3 =
(6)
227µ𝑉
𝑉𝑀𝑃𝑃𝑆𝐸𝑇 ∗𝑅3
𝑅4 =
(7)
0.0677𝑉
(𝑉MP(25ºC) +𝑅3 ∗
(6) 𝑅3 =
(7) 𝑅4 =
2𝑚𝑉∗18
227µ𝑉
𝑅𝑆𝐸𝑇
)−𝑉𝑀𝑃𝑃𝑆𝐸𝑇
= 158.6𝑘Ω
1.2∗158600
0.0677𝑉
)−1.2
1000
(9.12+158 600∗
= 10.2𝑘Ω
86
Design Schematic
Proving calculated values with the ti spreadsheet
87
F.2.2. TPS55340
Design
Using the step by step guide provided by Texas instrument in the TPS55340 datasheet, we
can calculate the values of the components of the boost circuit.
A few parameters must be known in order to start the design process. These parameters are
typically determined at the system level. Even though the bq24650 has a 0.5% charge voltage
regulation, we should give a wider range of input for protection purposes. By posing a 10% voltage
variation at the output of the bq24650, the input voltage range becomes 4.5 to 5.5V.
Parameter
Output Voltage
Input Voltage
Maximum Output Current
Transient Response 50% load step (ΔVOUT = 3%)
Output Voltage Ripple (0.5% of VOUT)
Value
12.6V
4.5 to 5.5V
1.5A
378mV
63mV
88
Selecting the switching frequency (R4)
The first step is to decide on a switching frequency for the regulator. There are tradeoffs to
consider for a higher or lower switching frequency. A higher switching frequency allows for lower
valued inductor and smaller output capacitors leading to the smallest solution size. A lower
switching frequency will result in a larger solution size but better efficiency.
The switching frequency is set by a resistor (RFREQ) connected to the FREQ pin of the TPS55340.
The resistor value required for a desired frequency can be calculated using eq.1.
𝑅𝐹𝑅𝐸𝑄 = 57500 ∗ 𝑓𝑠𝑤 (𝑘𝐻𝑧)−1.03 (1)
By choosing a switching frequency of 300 kHz, we can calculate the value of the resistor:
𝑅𝐹𝑅𝐸𝑄 = 57500 ∗ 300−1.03 = 161.52 𝐾Ω
The closest standard value is 162 KΩ
Determining the duty cycle
The input to output voltage conversion ratio of the TPS55340 is limited by the worst case
maximum duty cycle of 89% and the minimum duty cycle which is determined by the minimum
on-time of 77 ns and the switching frequency.
The duty cycle at which the converter operates is dependent on the mode in which the converter is
running. If the converter is running in discontinuous conduction mode (DCM), where the inductor
current ramps to zero at the end of each cycle, the duty cycle varies with changes of the load much
more than it does when running in continuous conduction mode (CCM). In continuous conduction
mode, where the inductor maintains a minimum dc current, the duty cycle is related primarily to
the input and output voltages as computed below. Assuming a 0.5 V drop across the Schottky
rectifier, we can calculate the duty cycle range using eq.2.
𝐷=
𝑉𝑂𝑈𝑇 + 𝑉𝐷 − 𝑉𝐼𝑁
(2)
𝑉𝑂𝑈𝑇 + 𝑉𝐷
• VOUT is the output voltage of the converter in Volts
• VD is the forward conduction voltage drop across the rectifier or catch diode in Volts
• VIN is the input voltage to the converter in Volts
At 4.5V, 𝐷 =
12.6+0.5−4.5
At 5.5V, 𝐷 =
12.6+0.5−6.03
12.6+0.5
= 66%
12.6+0.5
= 58%
Selecting the inductor (L1)
The selection of the inductor affects steady state operation as well as transient behavior
and loop stability. These factors make it the most important component in power regulator design.
There are three important inductor specifications: inductor value, DC resistance and saturation
current. The minimum value of the inductor should be able to meet inductor current ripple (ΔIL)
requirement at worst case. KIND is a coefficient that represents the amount of inductor ripple current
relative to the maximum input current (IINDC = ILavg). The maximum input current can be
89
estimated with eq.3, with an estimated efficiency based on similar applications (ηEST). For CCM
operation, it is recommended by Texas instruments to use KIND values in the range of 0.2 to 0.4.
For this design, we will choose KIND = 0.3 and a conservative efficiency estimate of 85% with the
minimum input voltage and maximum output current.
𝐼𝐼𝑁 𝐷𝐶 =
𝑉𝑂𝑈𝑇 ∗ 𝐼𝑂𝑈𝑇
(3)
ɳ𝐸𝑆𝑇 ∗ 𝑉𝐼𝑁 𝑚𝑖𝑛
𝐿𝑜 𝑚𝑖𝑛 ≥
𝑉𝐼𝑁
𝐷
∗
, D ≠ 50%, 𝑉𝐼𝑁 with D closest to 50% (4)
𝐼𝐼𝑁 𝐷𝐶 ∗ 𝐾𝐼𝑁𝐷 𝑓𝑆𝑊
12.6∗1.5
(3)𝐼𝐼𝑁 𝐷𝐶 = 0.85∗4.5 = 4.94𝐴
4.5
0.66
(4)  𝐿𝑜 𝑚𝑖𝑛 ≥ 4.94∗0.3 ∗ 300 000 = 6.68µH
A standard 7.5 µH inductor can be chosen.
After choosing the inductance, the required current ratings can be calculated. The inductor will be
closest to its ratings with the minimum input voltage. The ripple with the chosen inductance is
calculated with eq.5. The RMS and peak inductor current can be found with eq.6 and eq.7. It is
generally recommended for the peak inductor current rating of the selected inductor be 20% higher
to account for transients during power up, faults or transient load conditions.
𝑉𝐼𝑁 𝑚𝑖𝑛 𝐷𝑚𝑎𝑥
∆𝐼𝐿 =
∗
(5)
𝐿𝑂
𝑓𝑆𝑊
∆𝐼𝐿 2
2
√
𝐼𝐿 𝑟𝑚𝑠 = (𝐼𝐼𝑁 𝐷𝐶) + ( ) (6)
12
𝐼𝐿 𝑝𝑒𝑎𝑘 = 𝐼𝐼𝑁 𝐷𝐶 +
∆𝐼𝐿
(7)
12
4.5
0.66
(5)∆𝐼𝐿 = 7.5∗10−6 ∗ 300 000 = 1.32𝐴
1.32 2
(6)𝐼𝐿 𝑟𝑚𝑠 = √(4.94)2 + ( 12 ) = 4.94𝐴
(7)𝐼𝐿 𝑝𝑒𝑎𝑘 = 4.94 +
1.32
12
= 5.05𝐴
𝐼𝐿 𝑝𝑒𝑎𝑘(+20%) = 6.06𝐴
So the final value of the inductor will be 7.5µH with a peak current higher than 6.06A.
Selecting the output capacitor (C8-C10)
90
The minimum capacitance needed for a given ripple can be calculated by eq.8. If high ESR
capacitors are used it will contribute additional ripple. ESR ripple can be neglected for ceramic
capacitors but must be considered if tantalum or electrolytic capacitors are used. It is very hard to
find a high capacitance with a high voltage ceramic capacitor so we will use an electrolytic one.
By taking into account the ripple voltage coming from the equivalent resistance of the capacitor,
which is of 0.05V, we can find the optimal capacitor value.
𝐶𝑂𝑈𝑇 ≥
𝐷𝑚𝑎𝑥 ∗ 𝐼𝑂𝑈𝑇
(8)
𝑓𝑠𝑤 ∗ 𝑉𝑅𝐼𝑃𝑃𝐿𝐸
𝐶𝑂𝑈𝑇 ≥
∆𝐼𝑇𝑅𝐴𝑁
(9)
2 ∗ 𝜋 ∗ 𝑓𝐵𝑊 ∗ ∆𝑉𝑇𝑅𝐴𝑁
𝐷𝑚𝑎𝑥
I𝐶𝑂 𝑟𝑚𝑠 = 𝐼𝑂𝑈𝑇 √
(10)
(1 − 𝐷𝑚𝑎𝑥
0.66∗1.6
(8) 𝐶𝑂𝑈𝑇 ≥ 300 000∗(0.063+0.06) = 28.62µ𝐹
0.8
(9) 𝐶𝑂𝑈𝑇 ≥ 2∗𝜋∗300 000∗0.378 = 1.12 µ𝐹
0.66
(10)I𝐶𝑂 𝑟𝑚𝑠 = 1.6 ∗ √(1−0.66) = 2.23𝐴
The most stringent criteria is the 28.62μF for the required load transient. Eq.10 gives a 2.23 A
RMS current in the output capacitor. The capacitor should also be properly rated for the desired
output voltage.
So a capacitor of 39µF, of a voltage rating of 50V will be enough.
Selecting the input capacitors (C2, C7)
At least 4.7μF of ceramic input capacitance is recommended. Additional input capacitance
may be required to meet ripple and/or transient requirements. High quality ceramic, type X5R or
X7R are recommended to minimize capacitance variations over temperature. The capacitor must
also have an RMS current rating greater than the maximum RMS input current of the TPS55340
calculated with eq.11. The input capacitor must also be rated greater than the maximum input
voltage. The input voltage ripple can be calculated with eq.12.
𝐼𝐶𝐼 𝑟𝑚𝑠 =
∆𝐼𝐿
√12
𝑉𝐼 𝑟𝑖𝑝𝑝𝑙𝑒 =
(11)
∆𝐼𝐿
+ ∆𝐼𝐿 ∗ 𝑅𝐶𝐼𝑁 (12)
4 ∗ 𝑓𝑆𝑊 ∗ 𝐶𝐼𝑁
91
(11)𝐼𝐶𝐼 𝑟𝑚𝑠 =
1.32
12
= 110𝑚𝐴
By choosing a 22µF capacitor, we will a obtain a ripple voltage of
1.3
(12)𝑉𝐼 𝑟𝑖𝑝𝑝𝑙𝑒 = 4∗300 000∗22∗10−6 + 1.3 ∗ 3 ∗ 10−2 = 0.044 + 0.0035 = 88.2𝑚𝑉
The chosen capacitor should have a voltage higher than 10V, even though the maximum voltage
input is 5.5V, to limit the effects of dc bias. An additional 0.1μF, 50V is located close to the VIN
and GND pins for extra decoupling.
Setting output voltage (R1, R2)
To set the output voltage, the values of R1 and R2 must be chosen according to the following
equations:
𝑅1
𝑉𝑂𝑈𝑇 = 1.229𝑉 ∗ ( + 1) (13)
𝑅2
𝑉𝑂𝑈𝑇
𝑅1 = 𝑅2 ∗ (
− 1) (14)
1.229
Considering the leakage current through the resistor divider and noise decoupling into FB pin, an
optimum value for R2 is around 10kΩ (as suggested by ti in the datasheet). The output voltage
tolerance depends on the VFB accuracy and the tolerance of R1 and R2.
12.6
(14) 𝑅1 = 10 ∗ (1.229 − 1) = 92.5𝑘Ω
The closest standard value is 93.1kΩ.
Setting the soft-start time (C3)
This capacitor will be used to set soft-start time and avoid overshoot. Increasing the softstart time reduces the overshoot during start-up. A 0.047μF ceramic capacitor is used in this design
(as in the ti example).
Selecting the Schottky diode (D1)
The high switching frequency of the TPS55340 demands high-speed rectification for
optimum efficiency. The diode’s average and peak current rating must exceed the average output
current and peak inductor current. In addition, the diode’s reverse breakdown voltage must exceed
the regulated output voltage.
So a Schottky diode of forward voltage 0.5V, an average current higher than 1.6A, a peak current
higher than 6.06A and a reverse breakdown voltage higher than 12.6 V.
Compensating the control loop (R3, C4, C5)
The TPS55340 requires external compensation which allows the loop response to be
optimized for each application. The COMP pin is the output of the internal error amplifier. An
external resistor R3 and ceramic capacitor C4 are connected to the COMP pin to provide a pole and
a zero. This pole and zero, along with the inherent pole and zero of a boost converter, determine
92
the closed loop frequency response. This is important for converter stability and transient response.
Loop compensation should be designed for the minimum operating voltage. By using the
spreadsheet tool located in the TPS55340 product folder at www.ti.com, we found that the values
R3=3.74kΩ, C4=0.068µF and C5=270pF are a good choice to compensate the control loop.
Proving calculated values with the ti spreadsheet
By using the spreadsheet provided by Texas instrument, we can prove that the calculated
values are optimal.
The input capacitors are higher than the value suggested by the spreadsheet (10µF) to limit the
voltage ripple. There is also a difference in the output capacitors because we didn’t use ceramic
ones.
Final design
93
F.2.3. TPS84620
Adjusting the output voltage
The VADJ control sets the output voltage of the TPS84620. The output voltage adjustment
range is from 1.2V to 5.5V. The adjustment method requires the addition of RSET, which sets the
output voltage, the connection of SENSE+ to VOUT, and in some cases RRT which sets the
switching frequency. The RSET resistor must be connected directly between the VADJ (pin 43) and
AGND (pin 45). The SENSE+ pin (pin 44) must be connected to VOUT either at the load for
improved regulation or at VOUT of the device. The RRT resistor must be connected directly
between the RT/CLK (pin 35) and AGND (pin 34).
The table below gives the standard external RSET resistor for a number of common bus voltages,
along with the required RRT resistor for that output voltage.
Table F.3.Standard RSET Resistor Values for Common Output Voltages
So we should use RSET=0.267 kΩ and RRT=165 kΩ.
Input Capacitor
The TPS84620 requires a minimum input capacitance of 100 μF of ceramic and/or
polymer-tantalum capacitors. The ripple current rating of the capacitor must be at least 450
mArms.
Output Capacitor
The required output capacitance is determined by the output voltage of the TPS84620. The
required output capacitance can be comprised of either all ceramic capacitors, or a combination of
ceramic and bulk capacitors. The required output capacitance must include at least 1x 47 μF
ceramic capacitor. When adding additional non-ceramic bulk capacitors, low-ESR devices are
required. The required capacitance above the minimum is determined by actual transient deviation
requirements. The table below shows the typical transient response values for several output
voltage, input voltage and capacitance combinations.
94
Table F.4. Output Voltage Transient Response
So we should use 2 capacitors, a 47µF ceramic one and a 100µF bulk one.
95
Circuit design
96
Annex G-BOMs
G.1. Camera side
Quantity
Name
Ref. number
Power supply
1
1
1
1
1
1
1801.2106-01
203.089.011
2CT3002-W04300
2CT3004-W04300
2CT3000-W0000W
3071-2
1
1
1
1
1
Switch
Switch Protection cap
Male 4 way connector
Female 4 way cable
Panel Waterproof Cap
1m Cable - black 22
AWG(0.5mm2)
1m Cable - red 22
AWG(0.5mm2)
BRIDGE RECTIFIER
Fuse-cartridge-time delay 5A
Fuse-PCB-time delay 10A
IP67 Fuse holder
PCB-PAD hole
1
1
1
1
Access point + antenna
Li-ion battery
AC power adapter
IP camera
1
Manufacturer
Distributor
Max 10A-250VAC
max 5A
max 5A
-
Price
(CHF)
2.25
1.9
5.95
15.65
1.9
1.05
MARQUARDT
MARQUARDT
MULTICOMP
MULTICOMP
MULTICOMP
Alpha wire
Farnell
Farnell
Farnell
Farnell
Farnell
Distrelec
3071-3
-
1.05
Alpha wire
Distrelec
KBL005
0477005.MXP
34.6925
3101.011
8015-1
If average=4A
250V-5A
250V-10A
250V-16A
-
3.2
3.05
0.851
2.7
24.8
Farnell
Farnell
Farnell
Farnell
Farnell
TL-WA7510N
T-1298A
SM-0555
SNB-5001P
12VDC-8W max
12V-9800 mAh
12VDC-2A
12VDC-3.7W max
58
40
6
280
Vishay
Schurter
Schurter
SCHURTER
Vector
electronics
TP-Link
na
na
Samsung
Tech mania
Dealextreme
Dealextreme
Amazon
97
G.2. Locomotive side
Quantity
Name
Ref. number
Power supply
1
Raspberry PI Mod.B
Mod.B
1
1
1
8 GB SD Card
Access point + Antenna
Diode bridge-single phase-full
wave
63V-10 000uF capacitor
Plastic box
12 to 5 DC to DC converter
36 to 12 DC to DC converter
Push Button NC
AC connector
Feed Through HDMI connector
Hdmi male to male cable 126cm
RCA connector
DC Jack
DC Plug
SDSDB-8192
TL-WA7510N
NTE5322
5V-700 mA(micro
USB)
12VDC - 8W max
140V-25A
B41231B8109M000
RS5705
TEN 5-1211
TEN 40-4812WIR
CCTPR00RD
JR-101
NAHDMI-W-B
PSG01512
SPC21366
1636 04
9-18 VDC
18-75 VDC
-
1
1
1
1
1
1
1
1
1
1
1
Price
Manufacturer
(CHF)
59
Raspberry PI
Distributor
10
58
7.45
SanDisk
TP-LINK
NTE
K55
Tech mania
Distrelec
13.3
41.15
27.1
267.25
8.95
3.05
28.7
5.28
3.95
2.5
3.55
Epcos
Hammond
Traco power
Traco power
Camdenboss
Multicomp
Neutrik
Pro signal
Multicomp
Lumberg
Farnell
Farnell
Farnell
Farnell
Farnell
Farnell
Farnell
DX
Farnell
Farnell
Farnell
Digitec
98
G.3. Solar panel BOMs
G.3.1. BQ24650
Quantity
Description
Manufacturer
1
1
1
1
NTC high presision thermistor
R1-71.5K,1%,250mW resistor
R2-100K,1%,250mW resistor
R3-158K,1%,250mW resistor
1
1
R5-2 ,1%,250mW resistor
1
2
R6-20 ,1%,250mW resistor
R7,R8-10K,1%,250mW resistor
1
1
1
RSET-1K,1%,125mW resistor
1
1
1
2
3
RSR-10m,1%,0.33W resistor
C1-2.2uF,10%,X7R capacitor
C3,C4-1uF,10%,X7R capacitor
C5,C7,C11-0.1uF,10%,X7R capacitor
1
C6-10uF,10%,X7R capacitor
Semitec
Vishay Dale
Vishay Dale
Vishay BC
components
Vishay Dale
Stackpole
Electronics Inc
Vishay Dale
Stackpole
Electronics Inc
Stackpole
Electronics Inc
Stackpole
Electronics Inc
Stackpole
Electronics Inc
Vishay Dale
Kemet
AVX
Kemet
Vishay BC
components
TDK
Corporation
Manufacturer's Ref.
number
103AT-2
CMF5071K500FHEB
CMF50100K00FHEB
HVR2500001583FR500
Distributor
Ebay
Digikey
Digikey
Digikey
Price per unit
(CHF)
1.9
1
1
0.6
CMF5510K200FHEB
RNF14FTD2R00
Digikey
Digikey
0.7
0.3
CMF5020R000FHEB
RNF18FTD10K0
Digikey
Digikey
1
0.2
RNF14FTD5K23
Digikey
0.2
RNF14FTD30K1
Digikey
0.2
RNF18FTD1K00
Digikey
0.2
CMF5010R000FHEB
C340C225K5R5TA
CK06BX474K
C330C105J5R5TA
A104K15X7RF5TAA
Digikey
Farnell
Farnell
Farnell
Farnell
1
4.15
2.9
1.4
0.323
FK16X7R1E106K
Digikey
0.7
99
1
C8,C9-10uF,10%,X7R capacitor
1
1
1
C10-22pF,10%,X7R capacitor
D1,Diode schottky 40V 3A
D2,Diode schottky 30V 200MA
2
1
1
D3-D4,LED green clear 0603 SMD
Q1-Q2,Dual N-Channel 40-V (D-S)
MOSFET
L,6.8uH 6.2A
1
IC current source
1
IC Battery charger
TDK
Corporation
AVX
AVX
Fairchild
Semiconductor
Lite-On Inc
Vishay
Siliconix
MURATA
POWER
SOLUTIONS
Texas
Instruments
Texas
Instruments
FK26X7R1C106K
Digikey
1.5
CK05BX220K
SD2010S040S3R0
BAT54C
Farnell
Digikey
Digikey
0.4
0.6
0.3
LTST-C190GKT
SI7288DP-T1-GE3
Digikey
Digikey
0.3
1.7
496R8SC
Digikey
1.75
LM234Z-6/NOPB
Digikey
1.2
bq24650
Farnell
7.05
100
G.3.2. TPS55340
Quantity
Description
Manufacturer
1
R4-162K,0.1%,250mW resistor
1
R1-93.1K,0.1%,250mW resistor
1
R2-10K,0.1%,125mW resistor
TE
CONNECTIVITY /
NEOHM
TE
CONNECTIVITY /
HOLSWORTHY
VISHAY DALE
1
1
1
R3-3.74K,0.1%,250mW resistor
L1-7.5uH,20% inductor
1
1
1
C5-270pF,10%,X7R capacitor
3
C8,9,10-Capacitor 39UF 35V
CORNELL
DUBILIER
NICHICON
1
1
1
22uF,20%,X7R capacitor
Diode schottky 40V 3A
DC/DC converter 2.9-32V 5A 2.9-38V
TDK Corporation
AVX
Texas instrument
HOLSWORTHY
COILCRAFT
VISHAY BC
COMPONENTS
KEMET
KEMET
Manufacturer's
Ref. number
YR1B162KCC
Distributor
Farnell
Price per
unit (CHF)
0.516
H893K1BYA
Farnell
0.531
PTF5610K000BY
EB
H83K74BYA
SPT38L-752MLB
A104K15X7RF5T
AA
CK05BX473K
C412C683K5R5T
A
CK05BX271K
Farnell
0.81
Farnell
Farnell
Farnell
0.79
2.85
0.323
Farnell
Farnell
0.671
0.251
Farnell
1.7
RNU1H390MDN1
KX
FK20X7R1C226M
SD2010S040S3R0
TPS55340PWP
Farnell
3.25
Digikey
Digikey
Farnell
0.7
0.6
12
101
G.3.3. TPS55340
Quantity
Description
Manufacturer
1
CAPACITOR CIN1,
25V 47UF
CAPACITOR CIN2,
16V 68UF
CAPACITOR COUT1,
10V 47UF
CAPACITOR COUT2,
10V 68UF
Resistor RRT, 165K
250mW
Resistor RSET, 267
250mW
BUCK SYNC 6A
Kemet
1
1
1
1
1
1
Manufacturer's
Ref. number
C2220C476M3R2CT
U
16TQC68MYF
Distributor
Price per unit (CHF)
Farnell
4.9
Digikey
2.3
Farnell
1.1
Digikey
1.3
Welwyn
GRM32ER61A476K
E20L
T520V107M010ASE
025
RC55Y-165KBI
Farnell
2
TE CONNECTIVITY
CPF0402B267RE1
Farnell
0.79
Texas instruments
TPS84620RUQR
Farnell
13.2
Panasonic
Murata
Kemet
102
Annex H – Overo gumstix
H.1. Description
The lab MIS has designed a camera based on the gumstix board. The lab has two versions
of this camera: one built around the gumstix overo water board, which does not have Wi-Fi
capability, and the other around gumstix overo fire board, which comes with a built in Wi-Fi
module.
A previous student has developed a program that saves the images only in case of motion, and
another student has developed a charger circuit for the camera so it can be fed by a solar panel.
My task was to write a program to send the images via Wi-Fi. The idea behind this is to develop a
truly autonomous-intelligent camera.
H.2. UTP vs. TCP
There are two types of Internet Protocol (IP) traffic [8]. They are TCP or Transmission
Control Protocol and UDP or User Datagram Protocol. TCP is connection oriented – once a
connection is established, data can be sent bidirectional. UDP is a simpler, connectionless Internet
protocol. Multiple messages are sent as packets in chunks using UDP. Since UDP is
connectionless, there is no guarantee that the data will arrive in order to the client, or even arrive
at all. That’s why we need to send the images via a TCP socket so we can be sure that the data will
arrive, and in order.
H.3. Ad-hoc network
H.3.1. Description
On wireless computer networks, ad-hoc mode is a method for wireless devices to directly
communicate with each other. Operating in ad-hoc mode allows all wireless devices within range
of each other to discover and communicate in peer-to-peer fashion without involving central access
points. An ad-hoc network tends to feature a small group of devices all in very close proximity to
each other. Performance suffers as the number of devices grows, and a large ad-hoc network
quickly becomes difficult to manage, but this does not concern us since only one remote PC will
be connected to the network. On the gumstix, we can easily program an ad-hoc wireless network
with DHCP server capability. The ad-hoc acts the same as an access point with the difference that
in ad-hoc mode, the power is not managed, so the emitter will always transmit at maximum power.
This is a drawback, especially since the camera will be powerd by solar energy but there still isn’t
a clear way to program the gumstix as an access point.
103
H.3.2. Steps to create ad-hoc network
Open a terminal and type the following commands:




nano /etc/network/interfaces
Change the wlan0 configuration inside the file, by adding the following lines and
commenting or deleting any previous configurations:
o auto wlan0
o iface wlan0 inet static
o address 192.168.2.2
o netmask 255.255.255.0
o wireless-mode ad-hoc
o wireless-essid gumstixnet
Save and reboot
Now the gumstix will create an ad-hoc network named “gumstixnet”, its IP will be
192.168.2.2.
H.4. System architecture
Fig.VI.1. System architecture diagram
The remote PC should be given a static IP address, because it needs to act as a server, always
waiting for the client (gumstix) to connect to it to accept a file transfer. In our case, the gumstix
is given the address 192.168.2.2 and the server 192.168.2.4.
104
H.5. Algorithms
H.5.1. Server (remote PC)
Fig.VI.2. Server code chart
After the creation of the TCP socket and assigning a port and an IP address to it, the program
will run in loop, waiting for requests from the client. When one is received, the program will
create a new .raw file and save the data received in it, then when finished gets back to the start
and wait for a new connection.
105
H.5.2. Client (gumstix)
Fig.VI.3. Client code chart
After the creation of the TCP socket and assigning a port and an IP address to it, the program will
run in loop, reading the .raw file and filling a 512 bytes buffer with the data, then sending it to the
server until the file ends.
H.6. Problems
The first problem is that the code written by the old student to register the images in case
of motion, was written for the camera based on the gumstix overo water, so it did not work on the
camera equipped with Wi-Fi, some parameters needs to be changed.
The second problem is that even though the code works perfectly between two computers running
Ubuntu, and to transfer a small file from the gumstix to the remote PC, but it does not work once
the file is larger than 2KB. Due to a certain error (probably from the compiler), the file transfer is
dropped and only 2KB are saved.
106
The third problem is that by changing the interfaces configuration file, so that the Wi-Fi interface
runs as an Ad-Hoc with IP 192.168.2.2, the settings takes place for 3 seconds after the boot and
then it’s dropped, the signal disappears. This is probably due to a bug in the system. To solve this
problem, we need to manually configure it each time after boot using the following procedure (but
this contradicts the purpose to design an autonomous camera).
Open a terminal and type the following commands:




ifconfig wlan0 down
ifconfig wlan0 address 192.168.2.2 netmask 255.255.255.0
iwconfig wlan0 mode ad-hoc essid gumstix-network
ifconfig wlan0 up
H.7. Solutions
To solve these problems, we probably need either to update the OS or change it to a more
stable Linux based one, that way we can change the compiler all together. As for the Wi-Fi, many
people on the internet are complaining about its instability.
H.8. Improvements
The developed client code should be added to the part of the code done by the old student,
where the file gets saved on the disk, by changing the path of the file to be send (in client.c)
according to where the images are saved.
This process takes a certain time during which the fps of the camera is dropped dramatically to
less than 1 frame. To solve this problem, we need to send the data immediately via the socket to
the server instead of saving it in a file.
H.9. Codes
H.9.1. Client.c
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <signal.h>
#include <ctype.h>
#include <arpa/inet.h>
#include <netdb.h>
#define PORT 20000
107
#define LENGTH 512
void error(const char *msg)
{
perror(msg);
exit(1);
}
int main(int argc, char *argv[])
{
/* Variable Definition */
int sockfd;
int nsockfd;
char revbuf[LENGTH];
struct sockaddr_in remote_addr;
/* Get the Socket file descriptor */
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
fprintf(stderr, "ERROR: Failed to obtain Socket Descriptor! (errno =
%d)\n",errno);
exit(1);
}
/* Fill the socket address struct */
remote_addr.sin_family = AF_INET;
remote_addr.sin_port = htons(PORT);
inet_pton(AF_INET, "192.168.2.2", &remote_addr.sin_addr);
bzero(&(remote_addr.sin_zero), 8);
/* Try to connect the remote */
if (connect(sockfd, (struct sockaddr *)&remote_addr, sizeof(struct sockaddr)) == -1)
{
fprintf(stderr, "ERROR: Failed to connect to the host! (errno = %d)\n",errno);
exit(1);
}
else
printf("[Client] Connected to server at port %d...ok!\n", PORT);
/* receive File to Server */
char* fr_name = "/home/ubuntu/Desktop/test.jpg";
FILE *fr = fopen(fr_name, "a");
if(fr == NULL)
printf("File %s Cannot be opened\n", fr_name);
108
else
{
bzero(revbuf, LENGTH);
int fr_block_sz = 0;
while((fr_block_sz = recv(sockfd, revbuf, LENGTH, 0)) > 0)
{
int write_sz = fwrite(revbuf, sizeof(char), fr_block_sz, fr);
if(write_sz < fr_block_sz)
{
error("File write failed\n");
}
bzero(revbuf, LENGTH);
if (fr_block_sz == 0 || fr_block_sz != 512)
{
break;
}
}
if(fr_block_sz < 0)
{
if (errno == EAGAIN)
{
printf("recv() timed out.\n");
}
else
{
fprintf(stderr, "recv() failed due to errno = %d\n", errno);
exit(1);
}
}
printf("Ok received from server!\n");
fclose(fr);
}
}
H.9.2. Server.c
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <signal.h>
109
#include <ctype.h>
#include <arpa/inet.h>
#include <netdb.h>
#define PORT 20000
#define BACKLOG 5
#define LENGTH 512
void error(const char *msg)
{
perror(msg);
exit(1);
}
int main ()
{
/* Defining Variables */
int sockfd;
int nsockfd;
int num;
int sin_size;
struct sockaddr_in addr_local; /* client addr */
struct sockaddr_in addr_remote; /* server addr */
char revbuf[LENGTH]; // Receiver buffer
/* Get the Socket file descriptor */
if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1 )
{
fprintf(stderr, "ERROR: Failed to obtain Socket Descriptor. (errno = %d)\n",
errno);
exit(1);
}
else
printf("[Server] Obtaining socket descriptor successfully.\n");
/* Fill the client socket address struct */
addr_local.sin_family = AF_INET; // Protocol Family
addr_local.sin_port = htons(PORT); // Port number
addr_local.sin_addr.s_addr = INADDR_ANY; // AutoFill local address
bzero(&(addr_local.sin_zero), 8); // Flush the rest of struct
/* Bind a special Port */
if( bind(sockfd, (struct sockaddr*)&addr_local, sizeof(struct sockaddr)) == -1 )
{
fprintf(stderr, "ERROR: Failed to bind Port. (errno = %d)\n", errno);
exit(1);
110
}
else
printf("[Server] Binded tcp port %d in addr 127.0.0.1 sucessfully.\n",PORT);
/* Listen remote connect/calling */
if(listen(sockfd,BACKLOG) == -1)
{
fprintf(stderr, "ERROR: Failed to listen Port. (errno = %d)\n", errno);
exit(1);
}
else
printf ("[Server] Listening the port %d successfully.\n", PORT);
int success = 0;
while(success == 0)
{
sin_size = sizeof(struct sockaddr_in);
/* Wait a connection, and obtain a new socket file despriptor for single connection
*/
if ((nsockfd = accept(sockfd, (struct sockaddr *)&addr_remote, &sin_size)) == 1)
{
fprintf(stderr, "ERROR: Obtaining new Socket Despcritor. (errno = %d)\n",
errno);
exit(1);
}
else
printf("[Server] Server has got connected from %s.\n",
inet_ntoa(addr_remote.sin_addr));
/*send File from server */
char* fs_name = "/home/root/img.jpg";
char sdbuf[LENGTH];
printf("[Client] Sending %s to the Server... ", fs_name);
FILE *fs = fopen(fs_name, "r");
if(fs == NULL)
{
printf("ERROR: File %s not found.\n", fs_name);
exit(1);
}
bzero(sdbuf, LENGTH);
int fs_block_sz;
while((fs_block_sz = fread(sdbuf, sizeof(char), LENGTH, fs)) > 0)
{
if(send(nsockfd, sdbuf, fs_block_sz, 0) < 0)
{
111
fprintf(stderr, "ERROR: Failed to send file %s. (errno = %d)\n", fs_name,
errno);
break;
}
bzero(sdbuf, LENGTH);
}
printf("Ok File %s was sent from server!\n", fs_name);
close (sockfd);
printf("[Client] Connection lost.\n");
return (0);
}
}
112
References
[1] “http://kb.linksys.com/Linksys/ukp.aspx?pid=80&vw=1&articleid=17415”, Linksys article Differentiating the 5 GHz and 2.4 GHz bands
[3] “http://www.solar-wind.co.uk/cable-sizing-DC-cables.html”, DC cable sizing calculator
[4] “www.networktechinc.com/pdf/m12vga-extender-railway.pdf”, Railway applications Electronic equipment used on rolling stock
[5] “http://www.gammon.com.au/forum/?id=11497”, Power saving techniques for
microprocessors
[6] “http://arduino.cc/en/Tutorial/ArduinoToBreadboard”, From Arduino to a Microcontroller on
a Breadboard
[7] “http://arduino.cc/en/Main/Standalone”, Building an Arduino on a Breadboard
[8] “http://www.diffen.com/difference/TCP_vs_UDP”, Building an Arduino on a Breadboard
[9] “http://www.radio-electronics.com/info/circuits/diode-rectifier/rectifier-filtering-smoothingcapacitor-circuits.php”, Capacitor smoothing circuits and calculations
[10] “http://elinux.org/RPi_Easy_SD_Card_Setup”, Raspberry PI SD card preparation
[11] “http://www.rfcafe.com/references/electrical/resistor-values.htm”, Standard resistor values
[12] “http://www.rfcafe.com/references/electrical/capacitor-values.htm”, Standard capacitor
values
[13] “http://www.rfcafe.com/references/electrical/inductor-values.htm”, Standard inductor values
113

Front facing railway camera

Transcription

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