Open Bicycle Grade Simulator

Bicycling is, of course, best done outdoors, but if you can’t go outside for whatever reason — and don’t have access to a velodrome — training simulators that hook up to your actual bike can be the next best thing. After a clavicle injury meant staying off an actual bike for some time, Matt Ockendon decided to upgrade his trainer to physically simulate the grade of hill that he’s virtually climbing or descending.

Commercial “incliners” can be quite expensive, so Ockendon’s goal was to see if he could get close to their capability of +20% to -5% grade at 10 percent of the cost. What he came up with appears to accomplish this goal, using power and speed data sent from his Tacx Neo trainer over an ANT+ to BLE bridge to an Arduino Nano 33 IoT in order to calculate the bike angle needed for the given conditions.

With angle data derived, a linear actuator is moved up or down as needed, using an L298N driver board, along with a logic level converter to allow the 3.3V Nano to interface with it. The bike’s angle is sensed via the Nano’s built-in IMU and a small I2C OLED display is provided for user interface. A short demo of the trainer in action (sans rider) is seen in the video below, and code is available here on GitHub.