The onboard photodiode receives the reflected IR light. Its resistance drops as the intensity of the received IR light increases.
Reflect IR light exceptionally well, resulting in maximum detection range.
The FC-51 consists of an infrared transmitter (transparent LED) and an infrared receiver (black photodiode).
Because the FC-51 outputs a simple digital high/low signal, it connects easily to any GPIO pin on an Arduino, ESP32, or Raspberry Pi. Wiring Diagram →right arrow Arduino 5V FC-51 GND →right arrow Arduino GND FC-51 OUT →right arrow Arduino Digital Pin 2 Sample Arduino Code
The transmitter constantly emits IR light at a specific wavelength. Fc 51 Ir Sensor Datasheet
The use of an IR LED pair allows the sensor to perform well under moderate ambient light conditions.
The FC-51 module houses an onboard or a standard LM393 voltage comparator IC, alongside an IR emitter and receiver pair.
If you are building a line-following robot, a tachometer, or a proximity alarm, chances are you’ve stumbled upon the . It is one of the most ubiquitous, low-cost infrared obstacle avoidance sensors on the market.
The blue potentiometer on the FC-51 adjusts the reference voltage for the LM393 comparator. This directly changes the detection distance. The onboard photodiode receives the reflected IR light
If no obstacle blocks the path, the light disperses, and the receiver detects nothing. When an object enters the detection range, the light bounces back toward the sensor.
It is commonly utilized in line-following robots, obstacle-avoiding vehicles, and automated counters.
Fine-tunes the reference voltage of the LM393. Turning it clockwise increases the detection range; turning it counterclockwise decreases it.
Unlike ultrasonic sensors, it cannot provide an exact distance measurement; it only indicates if an object is within the preset threshold. Typical Applications The FC-51 consists of an infrared transmitter (transparent
2cm to 30cm (Adjustable via potentiometer) Detection Angle: 35°
The FC-51 usually features a 3-pin header for easy connection: Power input (3.3V – 5V). GND: Ground connection. OUT: Digital output signal. Typical Applications Obstacle avoidance for smart cars or robots.
Connecting the FC-51 sensor to an Arduino is straightforward. FC-51 VCC -> Arduino 5V FC-51 GND -> Arduino GND FC-51 OUT -> Arduino Pin 2 Simple Arduino Code: