Air Quality Monitor

Air pollution is becoming more and more serious. The value of PM2.5 (referring to particulate matter with aerodynamic equivalent diameter less than or equal to 2.5 microns in ambient air) is a parameter index. The higher the value, the more serious the air pollution is. Due to the small suspended particles of PM2.5, people are beginning to pay more attention to the air problems. The popularity of the air purifier and fresh air system show the market demand. At the same time, there are more and more air quality monitoring products on the market, and how to choose a reliable air quality detector is what people care about. The core of the air quality detector is the sensor, through which the air quality of the environment around us can be sensed.

At present, the functions of air quality monitors on the market are almost the same. Basically, there are five data monitoring items, including PM2.5 value monitoring, VOC or formaldehyde monitoring, temperature and humidity monitoring, and carbon dioxide monitoring. Most of the sensors used in China are produced by the sensor manufacturer Zhengzhou Winsen. Let's take a look at the sensors used in air quality monitors.

1. Temperature and humidity sensor

With the improvement of the technological level and the reduction of the cost, the temperature and humidity sensor has gradually become the standard configuration of such products, and it is also an important indicator of the comfort of the air environment.

▲WHT20 MEMS CO2 temperature and humidity sensor

Winsen Technology's existing temperature and humidity sensors include digital temperature and humidity modules ZS03, ZS05 and polymer resistance temperature and humidity sensor MS-Z3. Based on its own research and high development advantages, Winsen Technology has launched a new MEMS temperature and humidity sensor WHT20.

The WHT20 series temperature and humidity sensor uses the temperature characteristics of transistor Vbe to achieve high-precision temperature detection.It is a single-chip solution that utilizes the change of dielectric constant after the medium absorbs moisture to realize environmental humidity detection, and combines the latest integrated circuit signal processing technology.High precision, accuracy ±2.0% RH and ±0.3 ℃. SMD package,excellent long-term stability under high humidity conditions.

2. CO2 sensor

The CO2 sensor is used to detect the carbon dioxide concentration in the indoor environment. If the carbon dioxide concentration is too high, people will feel chest tightness, hypoxia, difficulty breathing, and even suffocation. At present, the CO2 sensor with infrared principle is commonly used in the market. At present, the solid electrolyte has been basically eliminated. Because of poor accuracy, troublesome development and other problems, and customers need to calibrate and verify by themselves. The infrared CO2 sensor is calibration-free, high-precision, and has a long life; but its cost is slightly higher. Currently, the most used CO2 sensors on the market are the MH-Z19B infrared CO2 sensor and the MH-Z14A CO2 sensor. Today, we focus on MH-Z19B.

▲MH-Z19B NDIR CO2 sensor

The MH-Z19B infrared CO2 sensor is a general, small sensor that uses the principle of non-dispersive infrared (NDIR) to detect CO2 in the air, with good selectivity, no oxygen dependence, and long life. The infrared CO2 sensor has a built-in temperature sensor, which can perform temperature compensation.At the same time, the CO2 sensor module has digital output and analog voltage output, which is convenient to use.

3. PM2.5 dust sensor

▲ZH07 PM2.5 Sensor

There are two types of sensors used to measure particulate matter on air quality monitoring instruments. One is infrared dust sensor and the other is laser dust sensor. Only a few manufacturers of air quality monitors on the market still use infrared dust sensors. Most use PM2.5 sensors based on the principle of laser scattering. Although the cost will be higher, the monitoring data will be more accurate. The most used laser dust sensor is the ZH03A laser dust sensor module.

The ZH07 independently developed and produced by Winsen Technology.It is a general and miniaturized laser dust sensor module. According to the principle of Mie scattering, it can detect the dust particles existing in the air through professional algorithms and calibration detection process. ZH07 adopts the design of double-ear positioning holes, which is firm and convenient to install, and has good consistency and stability at the same time.With serial output and PWM output capabilities, small size, easy to integrate.

U Disk Portable Air Quality Detector Application Solution

Winsen MEMS air quality sensor uses MEMS technology to integrate this ultra-small size (5*5mm) sensor into the circuit of the U disk. Simply through the four indicator lights, you can judge the quality of the air quality. It can be used for high-end products. Customer can develop a corresponding mobile APP or computer client to view more detailed parameters.

Formaldehyde detection

Formaldehyde in the home is always a hot spot of concern, and we can also integrate formaldehyde sensors into the U disk.

Winsen electrochemical formaldehyde sensor has the characteristics of low power consumption, high precision, high sensitivity, wide linear range, strong anti-interference ability, excellent repeatability and stability, small size, high integration,simple installation etc. It is mainly used in the detection of formaldehyde in the field of civil environmental protection.

Nowadays, there are basically sockets with USB ports installed on the wall of the home, so that they can be directly plugged into the wall, and the formaldehyde situation in the home can be checked at any time through the mobile phone APP. , The new house is the most suitable for this kind of use. When you see that the formaldehyde concentration value decreases, it’s the right time to move in the new house.