Hey everyone, I took a different approach to the cassette tape speed and I found an alternative motor for driving cassette tape. I did simulations to play the cassette tape and the rpm varies between 20-50 rpm. The motor is small which is good becauseit keeps the small form factor.
Ok i'm just ordering parts for measuring RPM from EMF. Based off the overall project I think only an arduino pro mini or teensy might be used. Thats good because the cost to build this thing will dramatically decrease.