What is air quality sensor?
An air quality sensor is a device used to detect the concentration of pollutants in the air. It can usually measure two or more air quality indicators such as temperature, humidity, carbon dioxide, carbon monoxide, ozone, formaldehyde, benzene, PM2.5, PM10, etc. It is an important part of the air purifier and fresh air system.
What do air quality sensors measure?
Air quality sensors can usually measure particulate matter (such as pm1,pm2.5, pm10), various gases (such as ozone, carbon monoxide, carbon dioxide, methane, formaldehyde, tvoc, etc.) and some environmental indicators (such as: temperature, humidity, uv, illumination, etc.)
How does an air quality sensor work?
The air quality sensor working principle is to detect gas and particulate matter indicators in the air through optical, electrical, thermal and other methods. For example, the laser scattering principle is used to detect the concentration of particulate matter such as PM2.5 and PM10 in the air, the NDIR non-dispersive infrared principle is used to measure the concentration of carbon dioxide gas in the air, and the electrochemical principle is used to measure the concentration of ozone gas in the air.
Place the air quality sensor in the measurement area, and the sensor will automatically collect pollutant data and transmit the data to the data processor for processing. The data processor can convert the data into visual charts or numbers to let users understand the air quality situation.
How to monitor various climate factors and wirelessly communicate with heating, ventilation and air conditioning (HVAC) systems and other intelligent building management systems, while significantly decreasing maintenance costs.
As shown in the figure, the Air quality sensor consists of several parts, namely Non-isolated DC/DC power supply、Gas sensor、Particle sensor、VOC sensor、Energy storage、Digital processing、Signal input/output protection、Wireless interface、Output user interface.
Non-isolated DC/DC power supply
Many air quality and gas detectors are powered from a Lithium battery. Linear regulators can be a choice for designs requiring ease of design with added functionality including EMI filtering. Buck converters with high light load efficiency can be a choice for designs prioritizing maximum battery life. Boost converters can be a choice when designs are operating from a low voltage battery. Non-isolated DC/DC power supply includes Buck converters (integrated switch)、Buck-boost, inverting & split-rail converters (integrated switch)、Boost converters (integrated switch)、Load switches、Shunt voltage references、Linear & low-dropout (LDO) regulators、N-channel MOSFETs、Analog switches & muxesm, the Corresponding product models are TPS62A01A、TPS63031、TPS61291、TPS22902、TL431LI、TPS709、CSD17483F4、TS5A3157
Gas sensor
Gas sensing can be accomplished to various means including optical sensors (e.g. NDIR) and electrochemical cells. Fully integrated analog front-ends (AFEs) can be a choice for designs where time to market is critical. Instrumentation and operational amplifiers can be a choice for customers designing custom transimpedance and gain stages. Gas sensor includes Precision op amps (Vos<1mV)、General-purpose op amps、Comparators、Signal conditioners, the Corresponding product models are OPA2335、TLV9152、LMP7300、LMP91000
Temperature & humidity sensor
A VOC sensor monitors the concentration of volatile organic compounds. The bridge output of the sensors can be interfaced to the microcontroller in the system using programmable-gain amplifiers. Temperature & humidity sensor includes Humidity sensors、Analog temperature sensors、Digital temperature sensors, the Corresponding product models are HDC3022、TMP235、TMP106
Particle sensor
Air quality is greatly impacted by the amount of particle matter in the air. Instrumentation and operational amplifiers can be used to create the transimpedance and gain stages required to monitor airborne particle matter. Particle sensor includes Precision op amps (Vos<1mV)、Difference amplifiers、General-purpose op amps, the Corresponding product models are OPA2335、INA132、TLV9152
Energy storage
Air quality and gas detectors can include a battery for portability. A battery charger device can handle charging in systems that use a rechargeable battery. A battery fuel gauge device can provide information such as remaining battery capacity, state-of-charge, runtime-to-empty, temperature, and battery voltage. Energy storage includes Battery charger ICs, the Corresponding product models are BQ25570、BQ25505
Digital processing
A microprocessor monitors all the system sensors and controls the user interfaces. The design can use a dedicated microcontroller or a single system-on-chip solution which combines the microcontroller and radio on a single device. Alternatively, a microprocessor may be used to support more advanced functions. Digital processing includes MSP430 microcontrollers、Arm Cortex-M0+ MCUs、Arm Cortex-M4 MCUs、Sub-1 GHz transceivers、Low-power 2.4-GHz products、Wi-Fi products、Sub-1 GHz wireless MCUs、Real-time clocks (RTCs) & timers, the Corresponding product models are MSP430G2955、MSPM0L1306、TM4C123GH6PM、CC1120、CC2520、CC3100MOD、CC1312R、TPL5100
Signal input/output protection
An ESD protection device may be required for wired interfaces. Signal input/output protection includes ESD protection diodes, the Corresponding product models are TPD1E05U06、TPD2E001、TPD1E10B06
Wireless interface
An integrated microcontroller and radio topology can be a choice for designs desiring a device that has the application layer, wireless stack, and RF radio functionality on one chip with an integrated MCU for additional resource management. A dedicated RF radio can be a choice for designs requiring 2.4-GHz or Sub-1GHz wireless connectivity with the existing host processor handling the wireless stack and application. Wireless interface includes Sub-1 GHz transceivers、Low-power 2.4-GHz products、Other wireless products、Wi-Fi products、Sub-1 GHz wireless MCUs, the Corresponding product models are CC1120、CC2651R3、CC2500、CC3100MOD、CC1312R
Output user interface
The air quality and gas detector interacts with the a user through a series of LEDs. For example, displaying a green color can indicate good air quality while a red color can signify bad air quality. An LED driver with integrated charge pump can be a choice for designs with only one voltage rail which needs to be stepped up for driving LEDs. Output user interface includes RGB LED drivers、Noninverting buffers & drivers, the Corresponding product models are TLC59116、TLC5971、SN74LVC1G126
What are the advantages of air quality sensors?
Keep healthy
The most direct advantage of air quality sensors is to help you create a healthy living environment. It can not only monitor indoor air conditions in real time and remind you to open windows for ventilation in time, but also provide you with outdoor air quality conditions when you are about to go out. So that you are fully prepared and protected.
Multi-function
There are many types of air quality sensors on the market today. Users can choose one or more air indicators to monitor. Moreover, some manufacturers can also provide customized services and add monitoring indicators according to the user’s usage environment.
Easy to use
Most air quality sensors are simple to install. For indoor use air quality sensor, you only need to turn on the device and successfully connect the device to your mobile phone and computer. For industrial use air quality sensor, equipment in different locations needs to be connected to the monitoring host through wiring to achieve multi-point monitoring.
Wide range
At present, air quality sensor is no longer limited to monitoring PM2.5 and PM10 in the air. It can detect various common pollutants in indoor air, such as PM2.5, PM10, formaldehyde, VOCs, etc. It can even detect air environment parameters such as temperature, humidity, air pressure, etc., with a wide detection range.
High precision
With the continuous development of technology, the measurement units of air quality sensors are also constantly upgraded, and the measurement accuracy is getting higher and higher. Even low concentrations of harmful gases can be accurately detected.
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