I plan on installing a dashcam based on the raspberry pi (a tiny computer) and its camera. Because it so small, I think I found the ideal place for it. I have a samll compartment in front of the roof lights which is supposed to contain sunglasses. The rasperry fits perfectly into this aund because the cable of the camera is thin, I can actualy get it out from that compartment. But the problem is, where do I get power up there? The Pi takes 5V from a micro usb jack. I already have a cigarette lighter adapter to convert the 12V from there to 5. The main advantage is, that when the engine is turned off, this port does not have any power and the Pi shuts down. Is there a similar line somewhere up there? 12V and only enabled when the engine is on? Or does somebody know of a good way to extend the lighter port somehow to the roof lights, but without having a cable hanging in front of my face? Thx.
How about using the light's power? To make it only on with the engine, you could find where the cigarette lighter and ceiling light's wires are near each other under the dash and splice the lights into the cigarette lighter's power. You should be able to do this at the fuse block under the driver's side of the dash. Only issue would be that the lights would only be able to turn on when the cigarette lighter has power.
Yes, it has to. The power comes from the battery through the 15A "DOME" Fuse through a couple junction connectors. Eventually it ends up at J23 as a 12v source. Pin 1 of the ON-OFF-DOOR connector, a red wire, is the 12v power wire. However these are always live because the system is ground controlled. To turn things on, they connect the normally floating connection to ground to complete the circuit which is very common.
I was talking about the switched power, not the one that's always on. See the quote in my original post.
There are no + switched 12v sources in the headliner. You will have to run your own. Everything up there is switched ground based on switches, contactors, and/or ECUs.
For my dashcam I took power from the mirror (I have the auto-dimming one with garage opener). It's powered on in READY. There is a wire in the same bunch that is hot all the time. - Alex
I have a Scosche bluetooth system - it is mounted on the same panel where the lighter is, but I ran a wire from there under the dash, over to the door where it is tucked under the weatherstripping. From there it got tucked under the headliner until the rearview mirror where the wire pops out and I mounted the microphone. I had to pull the dash apart but it was quite easy - there are a number of youtube videos showing how to do it. This might not be the shortest path to get power up there, but it can be done pretty easily and the wires can be hidden.
When you took out the door frame panel did you have to disconnect the 12V to prevent accidental blowing of the curtain airbag?
I did not have to remove it. Once to the door the wire was easily tucked into a seam running all the way to the headliner.
But is that seam where the curtain airbag comes out from? I don't want the wire to be in the way of the airbag in case of an accident when the airbag is needed but blocked by the wire.
That is not something that I personally think is a concern. It is in the same area, but runs along the bottom of the bag. That being said I'm ok with it in my car but take a look at it and come to your own conclusion.