This is something I built for
a friend from
work (Matthieu) one thursday evening. It's used to wake up a
shut PC.
My friend has a computer that he uses to record shows from the TV.
It's pretty much a similar system to mine, except that my
TV-recording-computer also has some other duties so it's always on.
Matthieu on the other hand, doesn't want to keep his computer on all the
time, so the computer should be able to wake up automatically at a pre-set
time to record a scheduled show. And this is what this device enables.
So how does it work?
The device gets it's power from the Wake-on-LAN port
even when the computer is turned off. Before shutting down, the computer
tells this device through the parallel port when the computer wants to be
waken up again.
The computer can now shut down, and the device counts down the required
time. After the time has passed, the device starts the computer using the
Wake on LAN -port. Pretty simple, eh?
To those interested, the program for the microcontroller (Microchip PIC
16F84A) has been programmed using the
Jal programming language. You can
find the source codes and the compiled programs here:
pctimer.jal,
pctimer.asm,
pctimer.hex
The sources for the PC software:
wake.c
...And here's the schematic of the device:
You can read more about this at
Matthieu's blog entry about the device.