文档介绍：Intelligent temperature control humidifier
In work, study and daily life, the dry air has a lot of damage to human healystem. So the key design of multi point temperature detection system is composed of two parts: the design of the temperature sensor and the main control unit. The application range of temperature sensor, used widely in large quantities, but also the highest in all kinds of sensor head.
Plan one:
Using thermistors, can meet the needs of 40 degrees to 90 degrees Celsius degree measurement range, but thermistor precision, repeatability, reliability is poor, for the signal detection of 1 degree Celsius is not applicable. And in the temperature measurement system, the use of single-chip temperature sensor, for instance AD590, LM35 etc.. But these chip output are analog signals must be after a / D conversion can be sent to the single chip microcomputer, which makes the structure of the temperature measuring device is complex.
Scheme two:
In the temperature measurement system, traditional measuring method is analog signal remote sampling AD converter, and in order to obtain high accuracy of temperature measurement, it is necessary to adopt measures to solve by the long line transmission and measurement of switching and amplifying circuit zero drift caused by error compensation problem. The use of digital temperature chip DS18B20 temperature measurement, digital signal output. Easy to handle and control MCU, many peripheral circuits of the traditional temperature measurement method of eliminating. The physical and chemical properties of the chip is stable, it can be used for industrial temperature measurement devices, the better linear element. In 0 - 100 degrees Celsius, the maximum linear deviation is less than 1 degrees celsius. One of the biggest characteristics of DS18B20 with single bus data transmission, by the digital thermometer DS1820 and micro controller AT89C51 temperature measuring device, it directly to the output of the temperature of