Review on Digital Red/Blue LED Tachometer RPM Speed Meter with Hall 🔴 Proximity Switch Sensor NPN for LED Panels and Modules - EEEkit by Brandon Wynen

No instructions and description wrong. Does it work well, like one pulse per revolution of the tachometer? Yes. Two things that are important to know. #1, the magnet must have the correct polarity/pole, so double check before sticking or gluing anything. Ask how I know. #2, no instructions and no schematic, but this worked for me. Terminal #1 is your power supply (+) as well as the brown wire from the sensor. #2 is the power supply ground (-). #3 is the blue wire going to the sensor, #4 is not connected, and #5 is the black wire from the sensor.