Adhoc NUC - The Astrophotography Manual

Intelligent Capture PC Hub (Chris Woodhouse www.digitalastrophotography.co.uk)
With the advent of the Intel NUC series of PC's, a fully functional Windows unit, approximately 4"
square and consuming less than 10W makes the prospect of a reliable and portable image
acquisition system a reality. Coupled with built-in WiFi and a robust imaging program such as
Sequence Generator Pro, remote operation with an iPad is a possibility, dispensing with the need
for USB extenders. Since SGP's automation is such that the less than ideal GUI of Microsoft
Remote Desktop app is less significant. Microsoft Remote Desktop is a free app for PC, Mac and
iOS.
The objective is to have the NUC connected to power and USB peripherals only at the mount. It is
powered up with its power button and then operated remotely, either via a home network or an adhoc network, using Windows Remote Desktop (or similar). It should be able to be shutdown /
restarted remotely and its connections to the network should be automated so that there is no need
for monitor/keyboard connections.
To do this requires a few prerequisites:
The NUC has to power up without a logon screen, so that it can go on to automatically connect or
generate the WiFi network. It also needs a method to be re-booted or shutdown remotely, since
one can only log off in WRD.
The NUC to the right will eventually replace the StarTech USB over Cat 5 system sitting under the
monitor.
Setting up the NUC for WRD
In the NUC's control panel, select "System and Security" and click "Allow remote access" under the
System heading. Click "Allow a program through Windows Firewall" and scroll down to check that
remote desktop is enabled for home and private networks through the firewall.
Shutdown and Restart
This requires a small command (.CMD) file to be run (most conveniently via a shortcut on the
desktop). These are one-line text files, named say shutdown.cmd and restart.cmd. You can create
them in moments using notepad.
Windows 7 and 8 have a slightly different syntax:
Windows 7 restart: "psshutdown -r -f -t 5"
Windows 7 shutdown: "psshutdown -s -f -t 5"
Windows 8 restart: "shutdown /r /f /t 5"
Windows 8 shutdown: "shutdown /s /f /t 5"
The Windows 7 requires the PSTOOLS archive downloaded and the psshutdown.exe extracted
from the ZIP file and put in the windows/system32 folder. (A Google search finds it on
technet.microsoft.com)
These commands force quit applications and shutdown/restart after a 5 second delay.
Automatic Login
For the PC to fully engage, one needs to disable the logon password screen. In Windows 7, typing
"netplwiz" in the Start menu box brings up the User Accounts dialog. Deselect "Users must enter a
user name and password to use this computer". You may have to type in your password to
confirm.
Setting Up Home Network
While at home, the most convenient way to connect to the NUC is via your wireless router. RDP
needs the IP address of your NUC. Most routers dynamically assign IP addresses, depending on
the order of connection. To fix an IP address, most routers allow you to set a static IP address for a
particular device. You will need to find out how to do this on your particular router. My Airport router
is very easy, I just type in the MAC address of the computer (found in the wireless network
connection status and often called "physical address" and is made of 6 groups of two hexadecimal
characters) and assign an IP address, something like 10.0.1.3. In your Network Connection Details
screen on the PC, this becomes the IPv4 address of the connection.
In the RDP settings on the remote PC or iPad, this IP address is entered "PC name" and your
normal NUC user name and password are entered into fields of the same name.
On the NUC, connect to your home network with applicable security passwords and ensure it is set
up for auto connection (look in Network and Sharing Center, on the manage wireless networks
tab).
You should be able to power up the NUC and then head over to your remote PC/Mac/iOS device
Setting Up an Ad-Hoc Network
This is useful if you are away from your home network and want to set up a direct link between the
NUC and your remote PC/Mac/iOS device. This is slightly more tricky, and so far, I have only been
able to do this through an unsecured network:
Click on the network icon in the taskbar
Click Open Network and Sharing Center > Manage Wireless Networks > Add
Manually create a network profile
Enter the network name (SSID), and no authentication (open) or encryption (work in progress to
find a way to get this secure)
• Uncheck "Start connection automatically" and "Connect even if the network is not broadcasting"
• Click Close
• Cick Start and in the search box type "CMD", then Enter
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• At the command prompt type "netsh wlan set profileparameter name=SSID
ConnectionType=IBSS", substituting "SSD" for your network name of your ad-hoc network.
• This will change the connection type to Ad-Hoc and you will no longer have to type in the network
key.
To get the ad-hoc network to be setup automatically when the NUC powers up, you need to add a
command to the startup commands:
• Click Start > All Programs > right click Startup and click Open
• Right click on empty space and click New > Shortcut
• Type in "netsh wlan connect SSID" (again, substitute "SSID" for the name of your ad-hoc
network)
• Click next and enter a name for the command, something like "auto adhoc"
• Click Finish
In Practice
Depending on whether I am at home or remote, I have two Startup shortcuts on the NUC, like the
one above, one for the home network and another for the Ad-hoc. I keep one on my desktop and
the other in the Startup folder, switching them over when I change venue. My NUC seems to have
a consistent IP address for its ad-hoc network. You find this in the network status dialog (IPv4) and
use this in the WRD settings as the PC Name, as before. So, on my iPad / Netbook, I have two
WRD connection settings, one for home and another for away. When I power the NUC down, or
restart it, I close the WRD connection before the NUC powers down. That seems to leave things in
a state that makes a subsequent re-connection more reliable. I have also noticed that WRD works
more reliably if the app is closed down and opened again after making changes to the connection
settings.
In situ, the NUC accepts a 12-19V feed and just requires a single USB cable into my interface box.
Inside, this feeds a 7-way industrial grade USB 2 hub for all the internal and external interfaces.