This project was a big one. Displaying text only GPS information on the screen in the car. The Pi has no way to use the touchscreen input so you control it with Tasker on a smart watch, using services from your phone. It shows you your speed, GPS Coordinates and the street you are on by default but can show more with a push of a button.

I recommend NOT trying this but the startonbt.sh code was fun so have a look if bluetooth and bash are your thing.

more info and code here