[Matthew Filipek] likes smart watches, but wanted to build one for under $100, so he did. The watch has a 1.7 inch LCD touchscreen, a rechargeable LiPo battery, an SD card, and Bluetooth. The watch is a little large since [Matthew] had only a month to complete the project that drove him to use some pre-made modules and meant one shot at getting his custom PCB right.
The watch sports three applications: a settings app, a simple game, and a sketch program (you can see a demo in the video below). Power management is a primary goal, of course, although the clock rate is held high enough to make the game playable. To simplify the software, [Matthew] uses protothreads–a lightweight thread abstraction for embedded systems.
We’ve seen several DIY smartwatches in the past including one entry for the Hackaday Prize. It is hard to roll your own watch that has the same small size and style as a commercial offering. However, there is something to be said for having a homebrew watch for boosting your hacker cred.