The project describes the construction of a contact-less tachometer by using a 8051 microcontroller and a proximity sensor to be used in counting the revolutions per minute of a rotating shaft. The ...

If you’re into anything even vaguely mechanical on the broad hacking spectrum, you’ve come into contact with things that spin. Sometimes, it’s important to know precisely how fast they are spinning!

It’s often necessary to measure a motor’s rotational speed without any physical contact with the motor or its shaft. Some methods use a mirror attached to the motor’s rotating part to reflect a pulsed ...