Temperature And Humidity Measurement System

Temperature and humidity are important parameters in the control system. Measuring temperature and humidity stably is important for the controling system.The traditional way to measuring the siginal of temperature and humidity is to use the analog sensors. After getting the signal, the circuit is added, which includes the signal amplification and hardware filtering to set the suitable range for the signal. Then the signal was sent to analog digital converter, and then to the MCU to be processed. However, this way increases the complexity of the system, making the system vulnerable to outside interferences, and the acquired signal is also unstable. After comprehensive consideration, the advanced SHT10 was chosen as the temperature and the humidity sensor and the C8051F020 was used as the MCU. The measuring way is measuing the temperature and humidity with 4 channels ,and processing the data with calculating the relative humidity and the dewpoint ,then transforming the data to LCD, and to the PC by RS-232. At last , the data was processed with the average filtering algorithm. A temperature threshold was set to control the output waveform of the DAC , and the controllable microwave source was controlled by the waveform.