I ride on Zwift using an old Schwinn Airdyne bike I got for $25 on Craigslist. It works great! I connected a bike computer magnetic pickup to the fan wheel, sp

I ride on Zwift using an old Schwinn Airdyne bike I got for $25 on Craigslist. It works great! I connected a bike computer magnetic pickup to the fan wheel, spliced it into a headphone cable, and plugged the headphone into a USB sound card connected to my laptop. On my laptop, I can monitor the microphone input and see each revolution of the fan wheel as a pulse. I wrote a program to convert these pulses to power (using Airdyne conversion formulas I found online) and then broadcast a Bluetooth power meter compatible with Zwift.