Photoeye sensor is a small electronic device that can detect changes in the light intensity it receives. The early Photoeye sensor used to detect the presence or absence of an object was a small metal cylindrical device. The transmitter had a calibration lens to focus the light towards the receiver. The receiver cable connected the device to a vacuum tube amplifier. . Inside the metal cylinder is a small incandescent lamp as the light source. These small and sturdy incandescent lamp sensors are the embryonic form of today's Photoeye sensor.

Photoeye sensor realizes its control function by converting changes in light intensity into changes in electrical signals. First, the transmitter is aimed at the target and emits the light beam uninterruptedly; second, the receiver receives the light beam emitted by the transmitter and converts it into electrical signals; then, the detection circuit detects the electrical signals output by the receiver, and only retains valid signals.
Photoelectric detection has many advantages such as high accuracy, fast response, non-contact, etc. Therefore, the Photoeye sensor has a wide range of applications in detection and control. The working principle of the Photoeye sensor is to realize the on and off judgment by blocking and conducting the infrared emission light, and the current change induced in the infrared receiving tube. Slot-type optocouplers are usually called slot-type photoelectric switches. They usually have a U-shaped structure. The transmitter and receiver are located on both sides of the U-shaped groove and form an optical axis. When the detected object passes through the U-shaped groove and blocks the light When the axis is turned, the photoelectric switch generates the detected switch signal. The photoeye sensor manufacturer tells you that the slot type photoelectric switch is safe and reliable for detecting high-speed changes and distinguishing transparent and translucent objects.