Hey Guys;
I am getting ready to put a Windows based PC in my car (a carputer) and I’m bashing my head against a wall trying to come up with a simple way of powering it on/off with the ignition key.

I’ve set the PC up so that it hibernates when the Power Button is pressed (it only takes 6 seconds to fully hibernate and 4 seconds to re-start Windows, not bad for a DDR2 667 with a 1.66 socket 479).

Powering on the PC with the ignition key is a simple enough affair by using a 555 timer configured as a “1 Second - One-Shot Monostable Oscillator” with the trigger closed and the output connected to a relay which in turn is connected to the PC power button.

Powering off the PC is where I’m having problems, I could use a normally closed relay connected to the accessories and use it to trigger another one-shot monostable when the key is turned off but this seems like a really convoluted way of building a circuit.

Does anybody have any ideas as to how I might build this into a single package? I’d be happy to pay for a schematic with the component values already calculated, I really need to get this project installed.

Thanks Guys,

Regards;
Mark W.​

 

Do you trigger the same button for turn off as well as turn on? If so you just need a single one-shot.

 

Do you trigger the same button for turn off as well as turn on? If so you just need a single one-shot.

Yes same button for both on and off, but the one-shot will only fire with power going to it, and once I turn off the key I lose that power,
Unless I were to use an NC relay connected to constant power and held open with accessory power and when I turn off the key it would then juice the one-shot,
that's kind of messy.

 

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