unusual shutdown controller

**turbochris** · 10-18-2009, 12:20 AM

I have a computer that is designed to run on 8 to 30 volts, which is great for a car but I'm having trouble finding a shutdown controller for it. It can be made to hibernate via one of the serial ports, so what I need is something that will close 2 relays when the ignition is turned on, when the ignition is turned off I'd like it to count about 10 minutes or so and open the first relay which will tell it to hibernate and after about a minute open the second relay to cut the main power. Having low voltage sense and a way to control it manually would be nice too. Any ideas?

**trader007** · 10-18-2009, 03:48 AM

like one of these? - http://store.mp3car.com/Automotive_S...ollers_s/9.htm

**turbochris** · 10-18-2009, 06:09 PM

I don't think that will support control through a serial port. it states that it's designed for control through the power button circuit and this usually means a single pulse where I need a closed circuit until hibernation.

**Curiosity** · 10-18-2009, 07:58 PM

You need something oldschool and that should work fine. Set your power button to hibernate, and let it take care of the rest. When you turn the key on, it will power the PC and push the power button to turn it on, then key off pulses the button to make it go into hibernation, then cuts power once it shuts down. You can mod the ACC sense to bypass it and such as well.

**turbochris** · 10-18-2009, 09:10 PM

I guess I should have mentioned, this PC doesn't have a power button, this is why I need to use the serial port to make it hibernate.

**nobb** · 10-18-2009, 09:19 PM

Do a search on here for the serial shutdown controller. You can use it to hibernate as well. As for the serial interface, nothing like that exists, but there are some fairly simple schematics on how to build it yourself. Basically all you need is a 12v relay and a serial cable. I used this when I used to have an inverter. Having a proper DC-DC is much more convenient though.

**Curiosity** · 10-18-2009, 10:55 PM

Yeah, that shouldn't be too difficult. Use the uSDC to hold the power on correctly, then ACC -> relay or optocoupler -> serial DTR line. The ACC off will trigger the shutdown software at the same time the uSDC expects the PC to be shutting down and starts its shutdown timer.