The DHT11 selected in this paper is a digital sensor of temperature and humidity. The external port of DHT11 is a single bus serial interface, and the length of data transmitted at one time is40 bit T, each data contains humidity and humidity calibration data, the data is sent in binary form, each bit of data starts from low level and lasts for a long timeAt 70us. The data is 0 or 1, which is determined by the duration of high level. The format of data bits is shown in Figure 3-4. When the duration of high level is 20us, the data is represented as0, the duration of high level is 50uS