A compact, non-contact digital tachometer that measures the RPM (revolutions per minute) of a rotating shaft using an Infrared (IR) sensor. A reflective mark on the rotor (or a slotted disc) produces pulses that a microcontroller counts and converts to RPM. The result is shown on a display (LCD/OLED) with options for max hold, averaging, and min/max capture. Ideal for labs, workshops, and project demonstrations.

Parts Used:

1. Microcontroller: Arduino Uno/Nano (or ESP32 for Bluetooth/IoT)
2. IR Sensor (choose one):
3. Reflective sensor (e.g., TCRT5000 module + LM393) with reflective tape/white mark, or
4. Photointerrupter (slotted) with a slotted disc for multi-PPR measurement
5. Display: 0.96″ OLED (I²C) or 16×2 LCD (I²C)
6. Buttons/Encoder (Optional): Set pulses-per-revolution (PPR), reset, hold/max
7. Power: 5 V USB adapter/power bank (separate battery optional)
8. Signal Conditioning: Built-in comparator or Schmitt trigger for clean edges
9. Enclosure & Mounts: Sensor bracket, disc/tape, wiring, connectors, fuse