i want do a car pc that doubles as my home theater pc made out of a intel i5 nuc. want use power brick to power the pc as htpc with power button, but when i put it in car i want to wire it to work with the ignition. i'm told for powering in the car to turn on and off with the key i need a Intelligent DC-DC Converter with USB Interface. i have read manuals and can't figure out how to do it. was wondering if anyone local may have a idea. i could cheap out and buy 2 but thats double the coast but less headache.
I know this is an old post but, what are you hoping to do with that machine in the car, I would say if you are interested in mild gaming you should look into a laptop, cooling and case are taken care of that way, and an aftermarket overhead entertainment system for the screen. That would be much easier to install/power. If you are looking to do mobile streaming browsing the simple solution would be any of the raspberry-PI type ARM based Android/linux devices. Most are very affordable, very small, easy to use, and are powered by 5v USB.
Because we sit in traffic with our kids constantly here in Hawaii I headrest mounted Kindle Fires(in GM headrests that originally had screens in them) and got bluetooth keyboards with Gyros for games. The original power supplies in the headrests were 12v, so that was an easy swap with a 2$ cigarette lighter to usb adapter(I gutted them, soldered them in, and heat shrinked the whole mess). All I do now is plug my phone in when i get in and turn on my hotspot, and they can both stream netflix on the road.