Measuring and Controlling Motor Speed With a Microcontroller

Sometimes it's really useful to accurately control the speed of a motor. Usually it's quite difficult, requiring a powerful transistor to switch power for the motor, and a photochopper to measure the speed. However, the fans you find in newer PCs (the ones with 4 wires) have control electronics and a position sensor built in! You could easily cut off the fan blades and use the motors for whatever you want!

In this video, I'll show you how to use an STM32F3DISCOVERY board running the Espruino JavaScript interpreter to control the fan speed in real-time!