Fc 51 Ir Sensor Datasheet -
const int irSensorPin = 7; // FC-51 OUT connected to pin 7 const int ledPin = 13; // Built-in LED
When an object enters the detection zone, it reflects the infrared light back toward the sensor.
There is a common confusion: the FC-51 can either be or Active HIGH depending on the manufacturer. The original design often outputs LOW when an object is detected and HIGH when no object is present . However, many clones invert this. Always test your module first. Fc 51 Ir Sensor Datasheet
The use of an IR LED pair allows the sensor to perform well under moderate ambient light conditions.
If you are looking for a complete copy of the technical document, you can view the FC-51 IR Sensor Datasheet on or refer to project guides on Instructables and Hackster.io . const int irSensorPin = 7; // FC-51 OUT
| Problem | Likely Cause | Solution | | :--- | :--- | :--- | | Output always HIGH | Sensitivity too low / Object too far | Turn potentiometer clockwise. | | Output always LOW | Sensitivity too high / Always detecting floor | Turn potentiometer counter-clockwise. | | Erratic output | Loose wiring / Power supply noise | Check connections; add a 100µF capacitor across VCC/GND. | | Detects only white, not black | Normal behavior | Increase sensitivity or move sensor closer. | | No output change at all | Wrong pin mapping or dead sensor | Test with multimeter: VCC = 5V, OUT should toggle when covering sensor with hand. |
When an object enters the sensor's field of view, the emitted IR light bounces off the object's surface. However, many clones invert this
The FC-51 IR Sensor: Your Robot’s Secret "Spidey Sense" Ever wondered how those clever little vacuum robots avoid tumbling down the stairs or crashing into your favorite vase? Most of the time, they’re using a "Spidey sense" powered by infrared light. At the heart of many beginner DIY projects is the FC-51 IR Obstacle Avoidance Sensor
Q: What are the applications of the FC-51 IR sensor? A: The FC-51 IR sensor has various applications, including robotics, automation, electronics projects, and industrial settings.
(Optional: Connect an LED via a 220Ω resistor to Pin 13 for onboard LED indication.)