When we started BitGym our goal was to make an experience which was easy to use and put very little between you and the experience. We developed our patented camera tracking technology so that you would not need to buy additional hardware, keep it charged, connect it over bluetooth, etc.
We do not have support for any external cadence or speed sensors. We've now seen such a variety of people, machines and rooms successfully use our camera tracking system with complete accuracy that our confidence in this decision has only growth. We understand it still has specific circumstances where it can fail, but we also believe there is always a tweak to the positioning or lighting to make to get it working reliably going forward and the app can walk you through those steps if you tap on the "tracking help" popup during exercise.
You can also contact support with a ticket if you have specific questions and we'll be happy to help.