This is a temperature and humidity composite sensor with calibrated digital signal output. It is applied to special digital module acquisition technology and temperature and humidity sensing technology to ensure that the product has extremely high reliability and excellent long-term stability. The DHT11 sensor consists of a resistive humidity sensing element and an NTC temperature measuring element, and is connected to a high-performance 8-bit microcontroller. Therefore, the product has the advantages of excellent quality, ultra-fast response, strong anti-interference ability, and high cost performance. Each DHT11 sensor is calibrated in an extremely accurate humidity calibration room. The calibration coefficients are stored in the OTP memory in the form of a program, and these calibration coefficients are called during the processing of the detection signal inside the sensor. The single-wire serial interface makes system integration simple and fast. Ultra-small size, extremely low power consumption, and signal transmission distance of up to 20 meters or more, making it the best choice for various applications and even the most demanding applications. The product is a 4-pin single-row pin package. The connection is convenient, and the special packaging form can be provided according to user needs.