CNY70 reflective optocoupler sensor

• Supply voltage of the LED: 5 V
• Maximum current of the LED: 50 mA
• The maximum collector-emitter voltage: 32 V
• Maximum collector's current: 50 mA

Details inthe documentation.

The sensor sends a beam of radiation through the IR transmitter, then measures the intensity of the  light reflected through phototransistor. The output is a voltage signal dependent on the light intensity falling on the detector. The more light will be reflected and get to photodetector, the higher wil be the output voltage. As the light is reflected better by the bright surface (dark surface absorbs it), the voltage will be higher on a white material.

1. IR transmitter, 2. Detector (phototransistor).

The sensors are readily used by designers of Line Follower robots to detect lines, as well as in the minisumo construction where it is used to detect the edges of the ring. As, in these cases, detected are the extreme values (to distinguish black from white - intermediate values are not important), the sensor can be located higher above the surface than the documentation indicates. From our experience, we can tell that with appropriate selection of resistors, sensors correctly distinguish the black insulating tape from the white background from a distance of about 1 cm.

In the industry, the systems can be used, for example, for edge detection or detection of objects at close range.The sensor has easy to install through the hole case. In addition, installed is the protection rim that allows you to completely squeeze the detector and transmitter to the surface.

The sensor consists of two main parts: a detector in the form of phototransistor, and transmitter as an infrared led. For the transmitter not to be damaged, you should limit its current (max. 50 mA), and, consequently, the infrared radiation power. This is done through the resistor connected in series (R3). For the proper operation of the phototransistor, necessary is the pulling-up resistor (marked on the figure as R4). The propert values must be selected using the documentation (example on the picture below).

• Documentation of CNY70
• A robot that uses sensors to detect the line