“A small hand-held tachometer that uses a laser to show how fast an object is rotating in revolutions per minute (rpm).
This Laser Tachometer is a rebuild of Elite Worm’s Build a Laser Tachometer. Both the hardware and software have be redesigned.
The original version by Elite Worm used a Arduino Nano. I decided to replace it with a ATtiny1614 microprocessor. This processor has a very low power consumption in sleep mode. The redesign is powered by a 3.7V Li-on battery and includes a TP4056 charger module to charge the battery.”