Hygrometer circuit and corresponding humidity measurement method

Abstract

The invention relates to a hygrometer circuit and a corresponding humidity measurement method. The hygrometer circuit comprises a humidity reference module, a humidity measurement module, a humidity calculation module, a sequential control module and a selection module, wherein the humidity calculation module takes a reference signal value as a reference and calculates a humidity value corresponding to a measured signal value in combination with the proportional relation between the reference signal value and the measured signal value. By use of the hygrometer circuit with the structure and the corresponding humidity measurement method, influence of resistance change on measured results can be avoided, measured values are basically nither influenced by outer environment temperature nor interfered by voltage and current of the circuit, the measurement accuracy is high, and the circuit is simple in structure, convenient to operate, lower in cost and good in adaptability.

Description

technical field [0001] The invention relates to the field of detection, in particular to the field of humidity detection, in particular to a hygrometer circuit and a corresponding method for realizing humidity measurement. Background technique [0002] In many environments, such as laboratories, warehouses and other environments, there is a high requirement on the ambient humidity, or there is a requirement to measure the humidity of the current environment. At present, the hygrometers on the market generally use the wet and dry ball hygrometry method and the electronic humidity sensor hygrometry method to measure humidity. Among them, the wet and dry bulb hygrometry method is relatively simple to maintain. In practical applications, it is only necessary to add water to the wet bulb and replace the wet bulb gauze regularly. It is more suitable for high temperature and harsh environments, but this method is not flexible enough, difficult to integrate, and difficult to Combin...

AI Technical Summary

Problems solved by technology

Among them, the wet and dry bulb hygrometry method is relatively simple to maintain. In practical applications, it is only necessary to add water to the wet bulb and replace the wet bulb gauze regularly. It is more suitable for high temperature and harsh environments, but this method is not flexible enough, difficult to integrate, and difficult to Data processing with computer

The electronic humidity sensor humidity measurement method uses semiconductor technology, which is highly integrated and easy to communicate with calculations, but it has requirements for the temperature of the environment used, and the internal resistance will change with the external temperature, which in turn affects Humidity measurement data, and when the voltage or current of the circuit changes in this humidity measurement circuit structure, the humidity measurement results will also be affected

[0003] Taking an electronic humidity sensor hygrometry method in the prior art as an example, this electronic humidity sensor hygrometry method usually chooses a capacitance-based relative humidity measurement method for humidity measurement, and uses the NE555 timing method in the prior art Take the humidity measuring circuit as an example to illustrate, the circuit structure is as follows figure 1 As shown, the NE555 timer humidity measuring circuit is mainly composed of a humidity-sensitive capacitor C and several resistors. The capacitor C can use a HS1100 humidity-sensitive capacitor. The timing function is realized through the NE555 timer, and the humidity-sensitive value is realized through the CC4060 counter circuit. The counting of capacitance oscillation, and finally the humidity value of the environment is calculated by looking up the table, and the circuit structure is powered by VCC. The internal timing of the NE555 timer is automatically timed, and the timing time is t. The oscillation period of C can get the oscillation times of the humidity sensitive capacitor, and then fit the relational expression between the oscillation times and the humidity according to the look-up table, and then use the software to substitute the oscillation times into the calculation to obtain the humidity value of the environment, although this method is from Theoretically, it is indeed possible to measure humidity, but it is vulnerable to external influences, and there are the following problems:

[0004] 1. In the actual circuit operation of this measurement method, the resistance in the circuit will change with the change of the external temperature, resulting in inaccurate final humidity measurement results;

[0005] 2. The timing function of the timer in the circuit is greatly affected by the voltage or current. When the voltage or current changes, the timing will be inaccurate, and the counting result will be inaccurate, so the obtained humidity value will also be inaccurate.

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