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Bike Power Meter with Crank-mounted WiFi Strain Gauges
Monday, 04 April 2016 10:01

In any motorsport, the more you know about how the engine is performing, the better a driver is likely to do in a race. That holds for bicycles, too, where the driver just happens to also be the engine. There are plenty of cheap bike computers on the market, but the high-end meters that measure power output are a bit pricey. [chiprobot] is looking to change that with a home-brew, low-cost bike power meter.

The project still appears to be in the proof-of-concept phase, but it’s an interesting concept for sure. The stock crank arms are carefully fitted with two pairs of tiny strain gauges. The gauges are wired in a Wheatstone bridge arrangement, with one gauge in each pair mounted perpendicular to the force on the crank to serve as a static reference. Output from the bridge is fed to an HX711 instrumentation amplifier. The demo video below shows how sensitive the bridge and 24-bit amp are.

The goal is to send crank data to a handlebar-mounted UI via WiFi with a pair of ESP8266 modules. We like the idea of a bicycle area network, but [chiprobot] has his work cut out for him in terms of ruggedizing and weatherproofing all this gear. We’ll be sure to keep an eye on this project. In the meantime, there’s plenty to learn from this bike power meter project we covered last year.

Filed under: transportation hacks, wireless hacks