1. What do I want?
I need a device that logs location, speed and course on an SD card. I could use my Android phone to do this, but the GPS would drain the battery within the hour. So let’s build a dedicated device.
Because it won’t have a display, it needs to have a way to show if it has a GPS fix. It needs to run on a 3s lipo (11,1v) for as long as possible (preferably >12 hours), but I also want it to warn me when the battery voltage gets too low because lipo’s should never be discharged below 3v per cell (9v total) or they get damaged.
All that must fit in a waterproof case. Why waterproof? That will be clear in a future post 🙂