(08-04-2021, 04:13 PM)jhornbr225 Wrote: Yes, I've attached several schematics. I was looking at the latest one I posted and I saw a couple minor mistakes, so I corrected them. There were a couple wires that were crossing without the humps, so I added humps for clarity.
My install is a little different than the typical configuration that I see on here. But the power circuit is almost the same.
I designed a circuit board in EasyEDA, had it manufactured, and then soldered parts to it.
I'm keeping my factory stereo, and using the power antenna output from it to turn on the Pi. I don't want the Pi to boot unless I turn my stereo on. I can live with the 30 some seconds it takes to boot up.
I use opto-isolators as inputs to my GPIO instead of relays.
I use relays to power my screen and reverse camera. My screen accepts video signal directly from my camera, and switches when I go into reverse. I find that to be a cleaner solution for me than trying to process the reverse camera in the Pi. I've added diodes and relays to power up the screen and camera when I switch into reverse, even without the stereo on.
In my drawing, the circles running down the middle signify terminals on my PCB. Stuff on the left is outside my PCB, (FRM-01, 12V to 5V regulator, screen). Stuff on the right is components on my PCB, (Diodes, opto-isolators, Relays, transistors, etc.).
I don't think to power the relay directly with a RPI Pin will function a long time. I would add a transistor to switch the relay and a flyback diode to protect the transistor for overvoltage. If the coil in the relay would be switched off it puts a high power impulse back into your circuit. Maybe a mosfed is better than a relay?
EDIT:
I misunderstood the relay in your schematic, if I'm right you switch with the relay GPIO17 to GND when the ignition is powered. But I think a relay isn't a good choice for that. You need definitif a flyback diode on the coil side. But the better solution is a Optocoppler.