In a word, an optical sensor is a light-based obstacle detection device. Strictly speaking, it is a combination device of photovoltaic components. Like other types of sensors, the main purpose of optical sensors is to measure and detect obstacles and send signals for tracking and monitoring. In terms of operating principle, optical sensors will be similar to ultrasonic and radar sensors.
1. Structure of the Optical Sensor
Basically, a photoelectric sensor consists of 3 main components:
+ Transmitter: Most of the optical sensors on the market today use LEDs as the emitter. Common types of LEDs are infrared LED, laser LED.
+ Receiver: is a phototransistor or optical transistor. This unit senses light and converts it into an electrical signal in a certain ratio. However, now this part is all replaced by ASIC (Application Specific Integrated Circuit) circuit. ASIC circuits will work more efficiently and accurately.
+ Output signal processing circuit board: is the central processing part responsible for converting analog signals to ON/OFF signals. This output is usually NPN or PNP format.
>>> Each component will have separate functions and support each other to form a complete optical sensor.
2. Working principle of Optical Sensor
To put it simply, the optical sensor emits light. When it encounters an obstacle, the light will bounce back. It will then process it to output a relay pulse signal. Like ultrasonic or radar sensors, only ultrasonic and radar use electromagnetic waves. The optical sensor will use light.
In fact, each type of optical sensor will have its own operating principle. However, basically, they still follow the rules of transmitting signals and receiving reflected signals.
Applications of Optical Sensors
- Inspect products passing through during washing, preliminary processing, packaging, finished products, etc.
- Check the path of cars, canned food, bottled water, etc. on the conveyor
- Identify high levels of coffee ink, soft drinks, liquids, .. in cans, boxes, etc.
- Counting bottles moving on high speed conveyor
- Detect missing labels on bottles
- Ensure safe control when opening and closing the garage door
- Turn on the faucet with the wave of your hand.
- Detect people and objects passing through the door
- Detecting a car in the parking lot
