SturmFront is a DIY fan-controller for indoor sports, which adjusts fan speed according to your current heart rate.
Commercially available is the Wahoo® KICKR Headwind, which has an integrated fan and regulates fan speed according to your power output. Keith Wakeham developed an open-source DIY fan controller named Maelstom. Maelstrom also adjusts fan speed according to your power output.
I developed SturmFront independently. A project description is also available: https://hannesweisbach.github.io/SturmFront/
I used KiCAD as EDA-tool. The controller is based on the Nordic Semiconductor NRF52832 SoC. I used the NRF5 SDK 17.1.0 in conjuction with the S332 softdevice to provide ANT+ and BLE connectivity.