Fc 51 Ir Sensor Datasheet -

void loop() sensorState = digitalRead(sensorPin);

Keep ambient IR low, adjust the potentiometer for your target reflectivity, and always confirm the pinout before powering up.

By referencing this , you now have the complete technical picture: pinouts, voltage limits, range adjustment, code examples, and troubleshooting. Whether you’re building a line-following robot, a contactless switch, or a factory counter, the FC-51 offers a straightforward “detect or not detect” solution that integrates with almost any microcontroller. Fc 51 Ir Sensor Datasheet

delay(50);

if (sensorState == LOW) // Object detected digitalWrite(ledPin, HIGH); Serial.println("Object Detected!"); else // No object digitalWrite(ledPin, LOW); delay(50); if (sensorState == LOW) // Object detected

| Symptom | Possible Cause | Solution | | :--- | :--- | :--- | | Output LED always ON | Potentiometer too sensitive; object too close; power supply noise | Turn potentiometer CCW; move objects; add capacitor | | Output LED always OFF | No power; broken IR LED; range too low | Check Vcc/GND; turn potentiometer CW; test with white paper | | Erratic detection | Ambient IR noise (sunlight, CFLs); loose wires | Shield sensor; use shorter wires; add 10ms debounce in code | | Very short range (under 5 cm) | Potentiometer misadjusted; black target | Recalibrate; use reflective tape on target | | Module gets hot | Reverse polarity | Immediately disconnect; check pinout version | How does the FC-51 stack up against common alternatives?

The FC-51 can run on 3.3V, making it safe for Pi GPIO. Use the same pinout but connect VCC to 3.3V. | Condition | Output Pin | Output LED

| Condition | Output Pin | Output LED | | :--- | :--- | :--- | | No object in front | HIGH (1) | OFF | | Object within set range | LOW (0) | ON | The FC-51 features a small, blue potentiometer (variable resistor) on the back of the PCB. Turning this potentiometer changes the comparator’s reference voltage, effectively adjusting the sensitivity.