This Instructable will show you how to make a Portable Digital Optical Tachometer using an Arduino Uno. This project is inspired from This instructable and is an enhanced version of it with an LCD display and a modified code.
Instead of a slotted sensor , it has a reflection based sensor. So :
1. You don’t have to worry about the thickness of the rotor
2. The number of blades won’t change your readings
3. It can also read the RPM of drum style rotors which slotted sensor can’t
What is a tachometer ?
A tachometer is a device used to measure the RPM or Revolutions Per Minute of any rotating body. Tachometers can be contact based or non-contact ones. The non-contact or contact-less optical tachometers usually use laser or Infrared beam to monitor the rotation of any body. This is done by calculating time taken for one rotation.