M2-ATX, so DC-DC. My real problem is that the motherboard doesn't have an ATX plug so is not able to signal the M2-ATX to shut off via pins 13 and 14 of the ATX connector.
ok so wire a relay this way:
acc from car
12v from molex on the pc
you NEED to put in diodes on this or you will cause a short
12v from the car
12v output from the relay, connect to the m2 12v input
this will make it so that when you turn the key on it'll close the relay and turn on the m2, when you turn the key off acc while shut off but the relay will stay closed because it's still getiing 12v from the molex on the pc, when the pc shutswoff 12v will go away and the relay will open cutting 12v to the m2
ok i just thought of something, the m2 controls the molex connectors right? if so it will continue to stay on, if the drives shutoff with the pc then you'll be ok, if not instead of a molex to control the signal just use one of the LED connectors at the mobo.
I see what you are getting at. But the LED connectors (HDD_LED and PWR_LED) are not 12V right? Aren't they 5V or 3.3V or something? Won't this cause an issue with the 12V coming from ACC?
Did you look at the timer I bought? I think I can just wire the timer into ACC and the have the timer control the open or closed state of the pin13, pin14 short on the 20pin ATX on the M2. When ACC goes off the timer start and when it is done it opens the connection between those two pins, which tells the M2 that the motherboard has powered down completely and the M2 then shuts off.
I see. I wish I knew more about this stuff. I got a D in electrical engineering at the Uni (crappy teacher).
I have a relay and diodes at home so I will give your idea a shot tonight as the timer hasn't arrived yet.
Thanks for all the help.
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Thanks for the tip. I got my timer today so I will start fiddling tonight.