void loop() sensorState = digitalRead(sensorPin);
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
| Feature | FC-51 | HC-SR04 (Ultrasonic) | TCRT5000 (Reflective) | | :--- | :--- | :--- | :--- | | | IR reflection | Sound wave echo | IR reflection | | Output | Digital (HIGH/LOW) | Analog (PWM width) | Analog/Digital (with add-on) | | Max Range | ~30 cm | ~400 cm | ~10 cm | | Color Sensitive? | Yes (dark objects reduce range) | No | Yes | | Cost | Very low ($1-2) | Low ($2-4) | Very low ($0.5-1) | | Best Use | Proximity switch, line follow (short range) | Distance measurement | Line following (very short) | | Yes (dark objects reduce range) | No
int sensorPin = 2; int ledPin = 13; int sensorState = 0; void setup() pinMode(sensorPin, INPUT); pinMode(ledPin, OUTPUT); Serial.begin(9600); int ledPin = 13
if (sensorState == LOW) // Object detected digitalWrite(ledPin, HIGH); Serial.println("Object Detected!"); else // No object digitalWrite(ledPin, LOW);