Network sensor of temperature & humidity based on RS485 interface

RS485 is an important communication protocol during CPU and external communication device, which is widely used in monitor-control system and project application. DS18B20 is used to test temperature in the sensor of temperature and humidity based on 89S52 MCU. ADC0831 is extended to convert the output signal of humidity sensor-NKHT, from which humidity value can be got. The value of temperature and humidity not only can be displayed on LCD, but also can be output using RS485 interface, from which network control system for temperature and humidity can be accomplished easily by users. The sensor has many advantages such as high precision, low cost, small volume, easy to construct network and so on.