How about adding this:

http://www.aaroncake.net/circuits/lightdrk.asp

You turn on the lights in the room when you enter, and the computer starts, when you leave, you turn off the light and clap your hands. To celebrate your achievements this day.

The problem is that you need a pulse to start the computer.

Ron

 

We start the computer by just pushing, momentarily, a normally open push button as I drew it. All we are doing is applying a momentary logic low to the motherboard. The key word here is momentary. Then in turn the motherboard latches a PSU ON line low going to the PSU. All you want and need to do is bridge that button with a negative pulse. We don't want to latch it but simple pulse it to simulate what happens when the button is pressed. Once the PC is on, it's on. The reason we pulse it is because once the PC starts if the start button is held the PC will do a hard shutdown. If you walk up to a running PC and just bump the start button, nothing happens. However, walk up to a running PC and press and hold the start button for 5 to 7 or so seconds and the PC will do a hard shutdown. Literally the PSU will shut down. Give me till tomorrow and I'll make a basic drawing.

Ron

Lovely! Thanks for your help! Made some readings on momentary buttons. Learning alot! (Y)

 

OK, another day in paradise begins.
Go back and take a look at the Clap Switch you linked to in your first post. Clap On / Clap Off. The circuit card is actually fairly easy to follow. If I look at the circuit card I only see two chips. At the top of the card beside the microphone I see a chip labeled MC 4558 which is a very common wide bandwidth dual bipolar operational amplifier. So we have a microphone and an amplifier chip with some components. I think we can assume the audio (clap) is picked up by the microphone and then amplified. There is even a little gain potentiometer up there with those parts. The next chip down is a 7400 very common quad NAND gate. My guess is the quad nand gate is configured as a gated RS Latch Flip Flop. Below that I see what looks to be a transistor and a relay. So the microphone picks up a bang or clap and amplifies it. There may be some filtering of the sound frequencies but there aren't many parts to the amplifier. The output is passed to what I figure is a flip flop (Clap Flip / Clap Flop). A clap turns on the relay and a clap turns off the relay.

If we clap twice quickly the output relay could be configured to start a PC. Remember we need a negative pulse on that button line that has 5 volts SB, we need to apply a brief logic low. While crude this would work. Connect the relay common terminal to the start buttons low side (PC ground) and the relay normally open terminal to the start buttons high side. Thus a quick momentary (clap clap) would start the PC just like pushing the start button. I say crude because it isn't the best way to go about it. One possible problem is we clap twice quickly and the PC starts. What happens if another loud sound triggers the card and relay? The relay will close which is the same at this point as holding the start button pressed. In that condition for about 5 to 7 seconds and the PC will do a hard shutdown. Spoke about those earlier. There are work around solutions but each step requires more parts and thinking. The idea is once you start the PC you would not want anything to cause a hard shutdown of the PC.

I could draw you a circuit but to build it would take some effort. So now we know how the PC starts, we know a hard shutdown is a bad thing, and we know what the clapper does as to latching.

Ron

 

@ Reloadron, glad to see you came to the darkside.

 

@ Reloadron, glad to see you came to the darkside.

After a busy few years before retiring I finally have the time to enjoy the forums. Thanks and I hope life has been treating you well. Just joined this forum and like it.

Ron