Background
I travel for a living and some hotels I stay at have spin bikes. I started carrying my own power meter pedals for the spin bikes so I could ride Zwift, but the experience just isn't the same without automatic resistance on the hills. Then one day I was looking down at that simple to turn knob and I had a thought - With the power meter pedals attached, almost everything is already in place on this $300 spin bike to turn it into the equivalent of a $3,000 computer controlled smart bike! And so here we are....
Thanks to some user requests, HR based power using an algorithm based on this page from Brian Mac is currently being tested. While no substitute for a true power meter (pedals or crank based) this provides very general average power information and is usable for steady state efforts.