Mh Sensor Series Flying Fish Ir Sensor Datasheet Fixed Direct

The datasheet says "20cm"? Lie. This is a proximity sensor, not a distance sensor. Max reliable range is ~2.5cm (1 inch). If you need long range, buy an ultrasonic or Time-of-Flight (VL53L0X) sensor.

Your object is too shiny or too dark. This sensor hates glossy white surfaces (reflects too well) and pure black surfaces (absorbs all IR). For line following, use white tape on black paper. Mh Sensor Series Flying Fish Ir Sensor Datasheet Fixed

void loop() { int sensorState = digitalRead(sensorPin); The datasheet says "20cm"

You don't need a "fixed" datasheet; you just needed the correct one. The MH Flying Fish is a TCRT5000 reflective sensor paired with an LM393 comparator. Treat it as a digital switch that triggers when something gets within 2cm. You don't need a "fixed" datasheet