After purchasing a basic foldable exercise bike, Thomas Schucker wondered if he could get a bit more out of it, perhaps even using it with virtual riding apps like Zwift and RGT. By default, this piece of equipment is set up to output cadence info via a simple headphone jack, using a demagnetized portion of the flywheel for sensing.

Taking this a step further, Schucker found that the magnetic field amplitude actually changes with the resistance input, allowing him to correlate the two with an analog sensor built into the Arduino Nano 33 BLE Sense.

The Nano is attached near the flywheel, and sends data over BLE, enabling him to use this rather cheap indoor bike in a much more involved way than it was likely ever intended. Code for the project is available on GitHub, while a demo of it controlling Zwift can be seen in the video below.