Remote Reboot Jig

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Developing Linux on a remote board can be challenging, because sometimes you'll need to reboot a crashed board. This can be simplified using a remote reboot jig consisting of a USB relay board.

Development jig.JPG

Here is a ASCII art diagram of the schematic:

 ------                        -------
|     +| ----[ USB relay ]----|+      |
| 5V   |                      | board |
|     -| ---------------------|-      |
 ------                        -------

Basically, you put the relay between the power source and the board on the Vbus line. You could do this by splicing a USB extension cord, by buying the appropriate power connector, or very fancy using a USB breakout board.

You can find a cheap USB relay on eBay, by searching for "USB relay smart home". Single channel suffices for 1 board, but you could go large, of course. Controlling the board (given you bought the HID "driverless" version) is done through this software:

jorik@neon:~$ cat bin/ 
hidusb-relay-cmd on 2
hidusb-relay-cmd off 2

Of course, on/off may need to be swapped, since the relay is SPDT.