The entire board radiates heat, and the IR transmitter LED may briefly glow very brightly before burning out. 3. Short Circuit on the OUT Pin
✅ The LM393 can run up to 125°C junction temp, but the plastic case and nearby components degrade faster above 80°C.
If you are an electronics enthusiast or an embedded systems engineer, you have likely encountered the FC 51 infrared obstacle avoidance sensor. It is cheap, reliable, and ubiquitous in Arduino and Raspberry Pi projects—from line-following robots to proximity alarms.
delay(100);
If you want to continue troubleshooting your hardware setup, let me know:
LM393 Comparator IC, Infrared Transmitter (Clear LED), Infrared Receiver (Black LED) Dimensions: 3.2cm × 1.4cm Why is Your FC-51 IR Sensor Getting Hot?
Run the sensor at instead of 5V. This cuts current by ~30%, reducing self-heating. Check your logic level converter if using a 5V Arduino. fc 51 ir sensor datasheet hot
2cm to 30cm (adjustable via potentiometer) Detection Angle: 35 degrees Output Type: Digital signal (0 and 1) Dimensions: 3.2cm × 1.4cm Pinout Configuration
One LED shows power status, while the second (usually green) lights up only when an obstacle is detected.
Inspect the underside of the FC-51 PCB with a magnifying glass. Look for accidental solder bridges between the LM393 pins or the potentiometer leads. Use a soldering iron and desoldering pump to clean up any messy factory joints. Standard Arduino Wiring and Code Template The entire board radiates heat, and the IR
The FC-51 is built around the , which ensures a stable digital signal. Specification Typical Value Operating Voltage 3.0V to 6.0V DC (Standard 3.3V/5V) Current Consumption ~23 mA (at 3.3V) to ~43 mA (at 5V) Detection Range 2 cm to 30 cm (Adjustable via potentiometer) Detection Angle Approximately 35° Output Type Digital (Low: Obstacle detected, High: No obstacle) Module Dimensions 3.1 cm x 1.4 cm (PCB) Pinout and Interface
Includes a Power LED (always on when powered) and a Signal LED that lights up only when an object is detected.
Slightly warm (5–10°C above ambient) is normal. If it’s hot to the touch (>50°C), you have a defective module or are running >6V. If you are an electronics enthusiast or an
The FC-51 utilizes an LM393 dual voltage comparator IC as its processing core to deliver a clean, fast-switching digital output signal free of continuous analog jitter. Core Parametric Ratings Rated Value Stable logic integration at Current Consumption ( ) Lower baseline draw Current Consumption ( ) Maximum typical draw due to IR transmitter Detection Distance Range Configurable via on-board trim potentiometer Effective Detection Angle 35∘35 raised to the composed with power Cone-shaped tracking path Output Type Digital Signal Active-LOW logic scheme Active Output Level Triggered when a reflection is registered In-Active Output Level Default state when line-of-sight is completely clear PCB Form Factor Overall length: including sensor LEDs Hardware Architecture & Pin Configuration