It's not the first DIY GPS data logger by a long shot, but Steve Cholewiak's new PIC16F88 Delorme Tripmate -- which Steve originally envisioned as a way to log his runs by carrying the unit in a backpack -- might very well be one of the cheapest. For under $20 you can snap up an old Delorme Tripmate off of eBay, and then set to work with Steve's detailed instructions. Sure, you'll need a few hax0r chops to begin with, and there's plenty of work to be done to get the Tripmate to spit out the right kind of data, and then store that data in an accessible way on some self-built circuits, but it's not like you had anything better to do this weekend, right?

[Via Hack-A-Day]