I. Project Introduction The digital thermometer is an electronic measuring instrument that is widely used in daily life and industrial fields to detect ambient temperature and convert it into a digital signal for display. With the development of modern science and technology, digital thermometers have gradually replaced traditional mercury thermometers and other methods, with advantages such as fast response, high precision, portability, etc. The digital thermometer designed based on 51 MCU is specifically applied to temperature detection in manufacturing, such as temperature controllers, oven temperature control, food processing, industrial furnaces and so on. The DS18B20 digital temperature sensor is used for temperature collection, the commonly used STC89C52 single-chip microcomputer control chip is used, and the 4-bit common anode digital tube is used to display the temperature data. When the set upper limit threshold is exceeded, the system will trigger the buzzer to alarm and prompt, thus ensuring accurate temperature control and safety. DS18B20 is a digital temperature sensor produced by Maxim Integrated. It uses a 1-Wire bus interface, which only needs one data line to simultaneously transmit data and power supply. Its main features are high precision, fast response speed, small size, and low price, and it is widely used in various temperature measurement occasions. The measurable temperature range of DS18B20 is -55°C to +125°C, with an accuracy of ±0.5°C (within the range of -10°C to +85°C). It integrates a temperature sensor, A/D converter and digital signal processing circuit inside, and can directly output digital temperature values. The working principle of DS18B20 is to use the effect of temperature on…