need help with circuits...

**spoolup** · 06-20-2009, 04:08 PM

hi guys
here's the scenario.
i want to power my xenarc off the lighter circuit.
i am looking for a circuit that will regulate 12V +/- .5v 1A and have a filter

on top of that, I am running my whole carpc audio thru my headunit.

i want the screen to turn on when i turn on the headunit.
i was going to run a simple relay circuit triggered from the remote plug to turn on the screen , BUT the screen's on/off button is a push button.
therefore i would need a circuit that the relay will be powered constantly but taking a power on/off signal from the remote to trigger momentarily off and on respectively instead of staying triggered (correct???)

could anyone help me out with these two?
thanks

**Curiosity** · 06-20-2009, 05:28 PM

Power the Xenarc from the Car PC PSU. It will automatically turn on when it's powered. Easy as that.

**spoolup** · 06-20-2009, 07:50 PM

hmmm..i don't want the screen to run all the time, tho.
i want it to run only when the headunit is on

**Bugbyte** · 06-20-2009, 10:53 PM

Okay, power the Xenarc from the PSU and put a switch inline. When you want the screen on, turn the switch on.

**colin** · 06-20-2009, 10:59 PM

Xenarc powered from PSU.
Relay attached the remote line from headunit, controlling power to Xenarc.

Makes sense to me...

**spoolup** · 06-21-2009, 04:40 AM

thanks colin. the prob is that the xenarc's switch is momentary on off not permanently in one position.
so i am in need of a circuit that'll momentarily trip the relay for on and momentarily for off.
which also reduces the project's switchery.......
i got the circuit for the 12v regulator last night so i'll be building that today and seeing how it fends for itself....

**colin** · 06-21-2009, 11:34 AM

No, screw the power switch. Set it to auto-on when it gets power. Then use the relay to cut power to the screen alltogether.

**spoolup** · 06-21-2009, 01:45 PM

thought about that too, makes it easier, but I thought i read somewhere that it doesn't retain the settings if you do it that way (brightness etc.)

come to think of it that doesnt make much sense does it?

that's the way it's gonna be! thanks dude.
i found the lighter psu that came with it too i'll "harvest" that and put all the circuits on one pcb.

question: instead of the remote switch, I could use the antenna line couldn't i?
the limit on it 150ma but it should be fine depending on the relay....