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Does anyone know of a free (preferably open-source) program that can wake up the computer from sleep/hibernate and do something, like play an alarm sound?

(Yes, this is possible -- Windows's SetWaitableTimer function allows you to set a "resume on sleep" parameter. And yes, I need to actually be able to wake up the computer, so programs that can't do this don't help.)

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up vote 3 down vote accepted

Windows task scheduler can do this. Run it, click create task, then go to the conditions tab. There's a checkbox for waking the computer to perform the task. You can then have it run a program. It doesn't actually need to be a program, you can just browse to your favorite mp3 file or whatever, and it will run whatever program is associated to play sound files.

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+1 this answer needs lots of upvotes! :D Thanks a lot! Just a question, though: Is there any way to put the computer back to sleep after the task, if it was already asleep? – Mehrdad Mar 26 '11 at 19:32
I don't think it does... One solution, a little ugly, is to schedule a 2nd task at the same time as your alarm. That task runs this:… – CreeDorofl Mar 26 '11 at 19:38
@CreeDorofl: I thought about that, but the problem is that it will run whether or not the computer was already asleep. :\ – Mehrdad Mar 26 '11 at 19:44
hrm, not sure why that wouldn't work... task 1 is your alarm sound. Task 2 runs right after that and forces sleep mode with that 2nd program. It can force it after 5 minutes or however much time you want. – CreeDorofl Mar 26 '11 at 19:48
@CreeDorofl: But what if the computer wasn't already sleeping? It should only sleep if the computer was asleep; otherwise, the computer might be busy with something, so we don't want to make it sleep. – Mehrdad Mar 26 '11 at 20:03

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