The present paper introduces one kind of new digital thermometer which takes MCU as the primary control component and takes DS18B20 as the temperature sensor. Mainly includes the hardware circuit design and the system program design. The hardware circuit mainly includes power circuit, the master control circuit, the display circuit , temperature sensor and serial communication circuit. The master control circuit uses STC89C52 and the temperature sensor uses DS18B20 which is produced by American DALLAS semiconductor company . The temperature can be measured on the system board ,displayed through two digital control, and monitored by PC through the serial interface . System circuit design uses Protel to complete ,hardware circuit is designed on the general board.
Because of using the advanced version of intelligence temperature sensor DS18B20 as examination component, compared with the traditional thermometer, this digital thermometer reduced the external hardware circuit, and has the characteristics of low cost and easy usage. The DS18B20 thermometer can carry on application development in different aspects:such as alarm in high temperature, temperature measurement with long-distance range and multi- spoo. So that it has a very good prospects for development.
Keyword: temperature sensor, DS18B20, STC89C52, Serial ports