Jeep Hud
I built this to live inside my Jeep's center console. It's powered by a Raspberry Pi Zero, and it uses data from various sensors (gps, accelerometer, compass, temperature) to provide data available via a webpage - which you can then see on the ipad mini. This does require connecting to the Jeep's hotspot.
To safely shut down the pi, the project has a small smart UPS that I built. It uses an Arduino pro micro to monitor voltage coming in from the Jeep to trigger the pi via gpio, then wait a few seconds before shutting off power from the battery.