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.
void loop() { int sensorState = digitalRead(sensorPin); Mh Sensor Series Flying Fish Ir Sensor Datasheet Fixed
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. The datasheet says "20cm"
Decoding the MH Flying Fish IR Sensor: Why Your Datasheet is Broken (And How to Fix It) Max reliable range is ~2
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.