hump de bump
Ok, so heres my problem for my screen i want to give it 12v regulated power, so i have this regulator, but my screen also draws its memory power from there. So i want to somehow rig something up that would give it power from one source when the acc line comes in and then it switches to another when that line drops out.
heres a pic i quickly made to help explain
hump de bump
my only thought is some sort of relay that is triggered when the power goes off. and have that inline with the current hookup
You could probably do the relay, but you might have problems because there'd be a moment where the circuit disconnected.
The other idea is see if you can get a cheap 12v regulator to throw in-line with the screen and battery.
Here ya go. I did the same thing for all my screens.
When car is NOT running, it take power from the battery, and get power from the regulator when car running.
87a (N/C) Input => go to ACC or Battery + (if you want full time on)
87 (N/A) Input => go to 12V (regulator output)
30 (COMMON) output => go to LCD +
86 (COIL -) go to car frame (battery -)
86 (COIL +) to go alternator charging circuit. This is only available when the alternator is turning/charging => car running. You may be able to find this at the alternator fuse in the camry.
it seems to me it would be better to have it controlled by the regulated output from the carPC... ie - (COIL +) to the regulator output, instead of the alternator charging circuit.
That way it would power the screen from the regulated output whenever it was available, and whenever the regulated output was shut off it would switch to the car battery power, as opposed to being determined by whether the car is running or not.
You may have to put a capacitor on the screen power input, because during the time when the relay is switching, it will have no power. The screen's internal power circuitry may have enough capacitance to continue working for those few dozen milliseconds, but if you have issues you might try it.
But don't take it from me! here's a quote from a real, live newbie:
eegeek.netOriginally Posted by Viscouse
i see what you guys are saying. ill go pick up a relay and do it.
Couldnt I even do the coil+ with the acc line? That would be the same as the regulator. But perhaps doing the regulator is the best idea, that alllows it to even close on the regulated power.
The reason I pick the charging circuit is that the only time I know that the input power is 14V+.Originally Posted by evandude
I don't want to use the PSU because it not always on in my setup.
excellent, problem fixed. you guys are great