Arduino compass
If your car’s dashboard does not feature compass, you might be interested in this DIY digital compass using Arduino and HMC5883L triple axis magnetometer. The direction you are heading is displayed on a tiny OLED.
Arduino powered digital compass
I’m astounded that some cars don’t have a digital compass always visible. You either have to launch the navigation app each time which may even disappear when you adjust the radio. In this project, you’ll create a digital compass that can be powered by by the cigarette lighter or another source (batteries make it handheld). You could buy one, but where’s the fun in that?
You’ll use an awesome OLED screen (with amazing viewing angles), a magnetomter, and Arduino (with a zombie apocalypse mode Easter Egg) to create this cool gadget. If you just want to see the code, I have it in a Gist:Compass.ino. I put it in a Gist so that other people can make edits and improvements to it.