How to power on/off an embedded pc??

[phofman]

Agreed. How do you make the power button (relay) activate for 1/2 second and then deal with the possibility of some software hanging and preventing the actual shutdown?

Using your finger?

 

[dangus]

Don't some UPS units output a control signal to the PC to shut-down when incoming AC fails?
If so you could hook-up this control signal from the UPS but not connect the PC AC power to the UPS.

The "basic signalling" method just involves shorting some serial port pins. The generic Windoze UPS driver (Control Panel, Power Options, UPS tab) will just shut everything down, or there's software like APC's "Powerchute" that will gracefully shut down applications (if that's necessary).

The PC can also signal the UPS when it's OK to shut itself down, which would be useful in some setups.

If someone hasn't already suggested it, take a look at the discussions at MP3car.com.

 

[stratus46]

Using your finger?

Well that's true but the point AIUI was to turn on / off the computer without any operator intervention. At least that's what I did for recording TV programs while we were on vacation 2 weeks ago.

I think the microcontroller solution will be the most robust and lowest cost - at least for me as I have them in the 'junk box'. Of course you could do something similar with 555 timers or other monostables but it would need at least 2 packages.

G²