How to use the watchdog on the RevPi Connect to also powercycle the relay

The FTDI EEPROM is patched as follows during factory end-of-line test
(and a reboot is performed afterwards for the change to take effect): 
devnum=$(cat /sys/bus/usb/devices/1-1.5.2/devnum)
sudo /home/pi/connect/patch_eeprom d:1/$devnum 0x14=0xaa 0x15=0x00


Now enable or disable the relay on a watchdog reset like this:
sudo /home/pi/connect/enable_relay_watchdog.py
sudo /home/pi/connect/disable_relay_watchdog.py

If you want the relay to be switched you have to enable it each time the RevPi 
is booted. Invoke the Python script enable_relay_watchdog.py from /etc/rc.local
or a systemd service to do this.

Be aware that /dev/ttyRS485 will briefly disappear when enabling or disabling
the watchdog.


revpi-connect-watchdog.sh is an example script showing how the watchdog timer 
can be restarted. It checks whether the Internet connection is operational by 
pinging the Google name server '8.8.8.8'. piTest is used to toggle the
watchdog bit in RevPiLED. Please note that this is only an example. 
You should integrate triggering into your application to check whether your
application works correctly.