Posts: 4
Joined: Thu Apr 12, 2018 5:45 pm

Potential Car Project

Thu Mar 26, 2020 4:28 am

Hello all! I have an idea for a car project and need some help in the planning portion. I did some digging and I really am not a fan of how other people made their radio from rpi so I have come up with a rough plan. Essentially I wish to create a touchscreen radio with an rpi 4(would have to buy) which can act as a radio and as a real time data monitoring system. Here's the simplest way I can explain:

- Overall power would come from 12v car battery
- Speaker power would come from factory wiring harness
- Speaker audio would come from the rpi connected to an amp(via aux to rca) connected to the speakers
- Rpi power would come from accessory port(car charger)
- Touchscreen power would piggyback off the rpi via an adapter board supplied with the screen
- Real time data monitoring through OBD2 to bluetooth

Now. My biggest concern is would adding this to everything else the battery supplies power to overload the system and cause electrical failures?(ie lights not working properly).The only thing i think would help is adding load equalizers but im not sure if that will do the trick.

Also is there a way to run both CarPi and OBDPi together? Not at the same time but sort of like apps on phones. Tapping on an icon would start the program(preferably a fast boot and not an insanely slow one). Then pressing an "x" or "close" button would go back to a main menu where I could switch to the other program.

Any help is appreciated. Thank you in advance!!

Posts: 432
Joined: Sun Dec 30, 2018 8:36 pm
Location: Denmark

Re: Potential Car Project

Thu Mar 26, 2020 3:52 pm

Powering a RPi from the car battery could empty the battery, so don't have it running all the time.
Other than that I don't see a problem adding a RPi to the car, provided you supply it through a fuse.

You mention: "Real time data monitoring through OBD2 to bluetooth"
If you're not going to use the OBD2 data in your solution then a simple OBD2 Bluetooth plug would be way easier to buy and install, compared to write software that does that task.

What's wrong with the other RPi car computer solutions you have looked at?
And which have you looked at?


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Posts: 3362
Joined: Tue Jun 20, 2017 12:16 am
Location: Australia

Re: Potential Car Project

Thu Mar 26, 2020 9:10 pm

- Rpi power would come from accessory port(car charger)
You should not do this. Having the power come from the accessory power means your Pi will abruptly lose power every time you turn your car off. This is not good for it.

You need to find a way to signal a start up / shut down based on the accessory power and power the Pi directly via a switching regulator connected to the battery via an appropriately rated fuse.

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