Fc 51 Ir Sensor Datasheet -
The FC-51 module features an onboard infrared transmitter (IR LED) and an infrared receiver (photodiode). When an object enters the sensor's field of view, the emitted IR light bounces off the object and strikes the photodiode. The module processes this analog change and outputs a distinct digital signal. Key Technical Specifications 3.3V to 5V DC Current Consumption: ~20mA at 5V
If the reflected light exceeds the set threshold, the comparator triggers the output, turning the OUT pin Low and lighting the green indicator LED. 4. Key Features and Adjustment
The changing voltage from the photodiode is sent to the LM393 voltage comparator IC. The LM393 compares this signal against a reference voltage set by the user via the onboard potentiometer. Fc 51 Ir Sensor Datasheet
| Parameter | Value / Range | | :--- | :--- | | | 3.3V – 5V DC | | Operating Current | 10 mA – 20 mA (typical 15 mA) | | Detection Range | 2 cm to 30 cm (adjustable) | | Optimal Detection Range | 10 cm – 15 cm | | Output Type | Digital (TTL: 0V or VCC) | | Output Logic | Active LOW (or HIGH – depends on board revision) | | Comparator IC | LM393 (Dual comparator, only one used) | | Infrared Emitter | 5mm IR LED (940nm wavelength) | | Receiver | Phototransistor (NPN type) | | Response Time | < 2 ms | | Adjustment | Onboard 10kΩ trimmer potentiometer | | Operating Temperature | -25°C to +85°C | | Board Dimensions | 32mm x 14mm x 8mm | | Mounting Holes | 2 x 3mm holes |
The module consists of several key parts that handle signal transmission and processing: IR Emitter: Sends out a continuous infrared signal. IR Receiver (Photodiode): Detects the IR light reflected back from obstacles. LM393 Comparator: The FC-51 module features an onboard infrared transmitter
The FC-51 module features a simple, standardized 3-pin interface, making it easy to connect directly to microcontrollers like Arduino, Raspberry Pi, or ESP32.
| Parameter | Value | |-----------|-------| | Response Time | ~2–10 ms | | Output Frequency | ~50–100 Hz (typical) | | Settling Time after power-up | <50 ms | Key Technical Specifications 3
The FC-51 is an active infrared proximity sensor designed to detect obstacles or surfaces within a short range. Because it uses light reflection to sense objects, it is commonly used in line-following robots, obstacle-avoiding cars, security systems, and factory assembly lines.
Direct sunlight or heavy incandescent lighting contains massive amounts of natural IR radiation. This can flood the photodiode, causing false positives or forcing the output to stay permanently LOW. Use physical shrouds or blinders around the sensor in bright rooms.