Finally sunshine and we take lab bike outside for testing. Shock. Bike is silent. The infrared (IR) cadence sensor no longer works. We check. All connections still good, Pi still booted, battery fully charged, speakers quietly hissing. Conclusion –  it’s too sunny! ie. the amount of natural IR is knocking our sensors off into an inaccessible range. We discuss modifying their range, covering/shading the sensors on the bike.. we reboot in the shade and try again. No good.

Conclusion #2. IR modules are not going to be workable on sonic bikes outside. Back to the drawing board. We decide to work with reading changes in a magnetic field created by cycling. ie. make a Hall sensor. Mount it on top of the chain ring pointing at the cog to read the peaks and troughs of the sprockets as they pass so making a pulse as before. Sukander builds and codes fast and by late afternoon this is the result. The Hall effect sensor works and we’re riding outside. Note how the rider can control/play with the sound, both forwards and backwards.