36 Techniques for Rotation and Rate of Rotation
Tachometers
Non contact measurements of rotation rate can be made with reflected light https://learn.adafruit.com/pro-trinket-tachometer/overview or detection of a moving magnetic field.
Non contact measurements of rotation rate can be made with reflected light https://learn.adafruit.com/pro-trinket-tachometer/overview or detection of a moving magnetic field.