The Aosong Electronic Co. Ltd, with a registered trademark ASAIR, is a leading designer and manufacturer in China of MEMS sensors. They focus on the design of sensor chips, the production of wafers, sensor modules, and system solutions. They have designed a sensor AHTT2820, which is a precision relative humidity and temperature probe.
ASAIR has based the design of AHTT2820 on the principles of a cold optical mirror. It directly measures humidity and temperature. Contrary to other methods of indirect measurements of humidity through resistance and capacitance changes, AHTT2820 uses the principles of a cold optical mirror. It can directly measure the surrounding humidity. It is an accurate, intuitive, and reliable sensor.
ASAIR uses a unique semiconductor process to treat the mirror surface of this high-precision humidity and temperature sensor. It uses platinum resistance to measure the temperature by sensing the change in the resistance due to a change in temperature. This gives the high-precision humidity and temperature sensor long-term stability, reliability, and high accuracy of measurement. The sensor features a fast response speed, a short warm-up time, and an automatic balance system.
Users can connect the sensor to their computer through a standard Modbus RTU communication system. It can record data, display the data, and chart curves. The precision RH&T probe provides direct measurement of temperature and dew point. Powered by USB, the split probe is suitable for various scenarios.
The AHTT2820 is a chilled mirror dew point meter that directly measures the dew point according to the definition of dew point. Various industries widely use it. They include food and medicine production industries, the measurement and testing industry, universities, the power electronics industry, scientific research institutes, the meteorological environment, and many others.
The probe uses its optical components to detect the thickness of frost or dew on the mirror surface. It uses the detection information for controlling the temperature of the mirror surface for maintaining a constant thickness of dew or frost. It uses a light-emitting diode to generate an incident beam of constant intensity to illuminate the mirror. On the opposite side, the probe has a photodiode for measuring the reflected intensity of the incident beam from the light-emitting diode.
The probe uses the output of the photodiode for controlling the semiconductor refrigeration stack. Depending on the output of the photodiode, the system either heats up or cools down the semiconductor refrigeration stack. This helps to maintain the condensation thickness of moisture on the surface of the mirror.
As it reaches the equilibrium point, the rate of evaporation from the mirror surface equals the rate of condensation. At this time, the platinum resistance thermometer embedded in the mirror measures the temperature of the mirror, and this represents the dew point.
Under standard atmospheric pressure, it is possible to obtain the related values of absolute humidity, relative humidity, water activity, and humid air enthalpy through calculation after measuring the ambient temperature.
The probe can measure temperatures from -40 to +80 °C, with an accuracy of ±0.1 °C. It measures humidity from 4.5 to 100%RH at 20 °C, with an accuracy of ±1%RH at <90%RH.