FC-51 infrared obstacle sensor for ARDUINO

The non-contact sensor FC-51 detects objects in the range of distances from almost zero to the set limit without coming into direct contact with them. The sensor is intended for use when information about the distance to the object is not required, but only about its presence or absence. The registration distance limit depends on the setting.

Sensor FC-51 has a discrete output. This is an optical sensor that registers an increase in the intensity of reflected infrared (IR) radiation in a controlled space. The change in the reflected radiation occurs due to the moving parts of the mechanisms or the movement of surrounding objects. FC-51 can be placed on a moving object to determine the position in the surrounding space. It is used to detect obstacles in the movement of wheeled and tracked machines. The sensor can become part of a visual aid for students in the field of control systems and automation.

The device contains an IR radiation source and a photodetector. The radiation is reflected from an obstacle and is recorded by a photodetector. It transmits a signal to the LM393 comparator, which is configured to operate at a certain level of illumination of the photodetector. The comparator generates a low or high logic level signal at the output of the FC-51 sensor.

Different reflection and absorption of radiation from different materials are used for the operation of the tachometer receiving unit. Let's say we have an engine. It is required to know the number of revolutions per minute of the motor shaft. FC-51 will help us out. It is enough to stick a piece of white paper on the flywheel, direct the sensor beam to the flywheel and get the tachometer receiving unit.

To reduce the consequences of various interferences, the processing microcontroller accumulates data received from the sensor in a short period of time and averages it. The FC-51 sensor can also work in devices that do not have a microcontroller.

The module is connected from 3 pins, where the VCC and GND pins are used to supply power to the module, and the received signal from the sensor is transmitted through the OUT pin.

There are two indicators on the module board. A glow of green indicates that the power is on. The red LED lights up when an object is in the detection zone.

Setting up the device is facilitated by the operation of the detection indicator. This allows the FC-51 to be configured to operate under real-world conditions. Setting the sensitivity of the sensor is performed using a trimmer resistor installed on the board. The obstacle is set at the required distance from the sensor photodevices. By turning the movable contact of the variable resistor on the board of the FC-51 module, the sensing distance is set, the red LED is turned on. Then the actuation distance is checked by moving the reflecting object.

Technical parameters of the sensor:

Supply voltage, V 3.3 ... 5
Detection distance to a reflective white matte plane, m 0.02 ... 0.3
Detection angle, ° 35
Dimensions, mm 43 x 16 x 7.