Automatic BMX Pump Track Timer

Hacker and BMX rider Ryan Bates has been going to an indoor bike park to practice his skills, and while the pump track there looks like a lot of fun, there was no good way to tell if your lap times were actually improving. Naturally, he got to work fixing it, using a pair of industrial-grade photosensors to check when a rider has started and ended a run.

The system runs on a custom Arduino-like ATmega328P board, featuring screw terminals for all the I/O as well as several other convenient power and connection features. As explained in his project video around 1:35, the main part of the code isn’t that interesting, as it boils down to an automatic digital stopwatch. His display code, however, is worth noting, as he modified a 4x28 character LCD screen to display as solid blocks for custom characters that combine together to form numbers as tall as the screen itself for better visibility.

It’s a brilliantly simple design, and is housed in a wooden enclosure that fits in nicely with the wooden hills of the bike park. One feature that is notably missing is a display for the best lap time. Since the device is easy to spoof by breaking the finish beam before the rider completes a lap, any resulting best time would instantly be in doubt!

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