As of May 28 2020, It is almost complete
I stopped working on this project for a while, but with COVID 19, I had more time. I finished most of the work on the app itself, except the bluetooth stuff, and now I just need to assemble the parts into something that can fit into the Double-Din stereo slot in my truck. I also need to figure out if the 12 volt switched power coming through the wire harness is enough for all the devices or will I have to put the amplifier on un-switched wire with a relay to make it switched too. I want everything switched. It does not need constant power like a lot of stereos do because they need the power to keep time and your radio stations saved. My stereo gets its time and date from GPS satellites and saves your info on a USB drive.
I also need to make the Raspberry Pi read-only so it can be shut off without shutting down the software. I'm going to move the home folder over to the USB stick that will hold all the media files so it can be written to. I'll probably move the /etc folder there too. Then make all the logs save to a virtual drive that gets erased every time it's shut off.
There shall be a youtube video soon, I hope