Fc 51 Ir Sensor Datasheet -

The LM393 comparator has an open-collector output on some designs, requiring a pull-up resistor internally. In practice, this means the signal idles HIGH and pulls LOW upon detection.

| FC-51 Pin | Arduino Pin | | :--- | :--- | | VCC | 5V | | GND | GND | | OUT | Digital Pin 2 (or any digital input pin) | Fc 51 Ir Sensor Datasheet