And the server can also restart wifi-router and cable modem if cannot ping the selfsame watchdog (and 8.8.8.8) at reasonable intervals.
Yes. They are watching each other.The server causes the Blue Led (aka "Sininen Ledi") to blink, so that I immediately know Watchdog is watching and gets nourishment. Sometimes I boot to some other distro and forget to turn off the Watchdog, which is annoying.
$ cat wifi-off
#! /usr/bin/python2
import parallel,time
p = parallel.Parallel() # open LPT1 or /dev/parport0
p.setData(0xFF)
$ cat wifi-on
#! /usr/bin/python2
import parallel,time
p = parallel.Parallel() # open LPT1 or /dev/parport0
p.setData(0x0)The easiest approach is to just use a commonly available relay modules used with Arduino or similar platforms/microcontrollers, as they already contain minimum or all protection mechanisms. So, the module will contain the reversed diode in parallel with the relay, while additional transistor and optocoupler will allow you a complete galvanic isolation of the controlling- from the and relay circuit.
YouTube has plenty of user-friendly resources with schematics and functional overviews, just search for "relay module" or "relay arduino".
Great overview though, thank you for posting that.
I'm always thinking I should buy an UPS but realistically I'd need it once every 5 years at best, and even then I'm usually lucky.
At one time it happened every day. This was because of open Telnet port. Crooks, mostly Russians, caused so many Telnet-open processes that machine choked up.