Update: 2019-12-06 16:35 Source: LUFTMY
Dust concentration sensor is mainly used for continuous monitoring of indoor dust concentration and other workplaces. In order to meet the existing indoor air quality real-time development of high-tech sensors in the natural state of light scattering theory of indoor monitoring dust concentration.
LD12 laser dust sensor (dust detector) is a high-tech product integrated with aerodynamics, digital signal processing and Optoelectronics independently developed by luftmy in Guangzhou. It is mainly used to detect the dust mass concentration (PM value) in the atmosphere. It is suitable for indoor air detection, urban grid monitoring, mobile monitoring and other fields and occasions. It is the core module of the air quality detection system.
Data accuracy: laser principle detection, industrial level photoelectric induction; high resolution: ≥ 0.3um, particle size, 0.001mg/m3;
Detection size: pm1.0 ~ PM10;
Stable performance: it can adapt to the composition of dust in different atmospheric environment and adjust the independent parameter coefficient;
Data transmission: UART, PWM;
Intelligent monitoring: real-time monitoring of various indicators of the sensor, when the abnormal state can be fed back to the user in time;
Dust concentration sensor, mainly used for continuous monitoring of total dust concentration in indoor dust monitoring places, is the core module of air quality detection system.
The structure and circuit of PM2.5 dust sensor based on infrared principle are relatively simple. Its light source is infrared LED light source. The air inlet and outlet are heated by resistance to obtain hot air flow activity. If particles pass through, it will output high level. The output signal is only PWM and IIC signal.
The structure and circuit of laser PM2.5 sensor are relatively miscellaneous, and its light source is laser diode. The sampling air is driven by the electric fan or blower, and tested by the disorderly planned air duct. When the fine particles in the air enter the area where the laser beam is located, the laser will scatter; the scattered light has radiation in 360 ° of the space. We place the photodetector in the proper position to only receive the scattered light, and then generate the current signal through the photoelectric effect of the photodetector. After the circuit is expanded and processed, the concentration value of the fine particles can be obtained. Generally, the output signal is serial port output. A single manufacturer outputs various particle size values such as PM10 together, and outputs values of PCS / L, mg / m3 and other units.
Infrared principle dust sensor has been used in the industry for many years, and the market price is about tens of yuan. The laser dust sensor is just emerging in the industry. The cost distance between the two is mainly due to the increase of organizations such as laser generator and fan in the latter's material cost and the need for disordered circuit structure, as well as a high skill threshold.
Measurement accuracy of the difference between laser dust sensor and infrared dust sensor. Because the particle signal scattered by the infrared LED is weak, it only responds to the large particles larger than 1 micron, and only uses the heating resistance to push the sampling air flow, so the number of samples is small, and the data accounting is completely done by the upper computer. The laser sensor can detect more than 0.3 μ m particles. Because of its own high-performance CPU, fan or blower is selected to collect a lot of data, which is analyzed by professional particle counting algorithm. In summary, it has more advantages than infrared dust sensor in sampling number, data source and algorithm.
Due to the lack of accuracy in the application occasions, the infrared principle sensor is mainly used in dusts and other rooms of industry and mining. The detection target is large particle size and high concentration dust, and the detection level is mg / m3, so it is unable to accurately measure the concentration of PM2.5. The laser principle sensor is mainly used in PM2.5 detection to quantify the quality of PM2.5. It can be embedded in the air detector and air purifier of household (vehicle and hand-held). In addition, the laser principle sensor is also used in the fields of Internet of things data collection, environmental quality detection, etc.
The trend is that before the laser principle sensor is used in the field of civil use, many infrared PM2.5 sensor modules are used in the air purifier. However, with the development of air purification industry, the cost of laser principle sensor of high sensitivity fine particle sensor is gradually decreasing, and the requirements of terminal customers for accurate measurement of air quality are also increasing. Choosing laser principle sensor and accurately quantifying PM2.5 quality have been recognized as the trend in the industry.