This system is a design of the speech thermometer according to the microprocessor AT89C51,which is used to measure the environment temperature, the scope is between zero and one hundred degrees .The whole design system is divided into 5 parts: A microprocessor control, temperature sensor,the LCD display, the speech report and the keyboard control circuit, at the same time ,we use the audio power amplifier LM386 to amplify the audio signal, in order to satisfy people’s desire of hearing. The whole design take AT89C51 as the core, use the one-wire digital temperature sensor DS18B20 which is made by the company of DALLAS to carry out the collection of the environment temperature and A/D transition, at the same time because its outputs is the numerical form and serial data transfer, so this makes the microprocessor deal with the data processing convenience but it also make us difficult to program, it request us must hold its reading and writing scheduling strictly. The microprocessor transforms the temperature value we collect from the temperature sensor, so that we can easily display it in the LCD display and the playback. The speech recoding & p layback I choose to use is the IC of ISD1420, it has high fidelity, good record effective, and economic. The LCD I choose is TC1602A, its power consume is low, it has many advantages , for example, the volume is small, the contents is abundant, super thin and agile etc, and its application is becoming more and more extensive. The whole design lies in the program, because its outer circuit is much more simple, and it can carry out more easily. In my thesis, there are flow chart and parts of subprogram and various hardware circuit diagrams.
Keywords:Microprocessor; Digital temperature sensor;The LCD display;Speech recoding & playback;Programme