Smart Door Lock System Design Based on UWB Technology

With the rapid development of intelligent technology, smart home system has gradually become part of modern life. Intelligent door locks as the first gateway to the smart home, is the security of every family is also the main development of the smart home. The current smart door lock system also needs to further improve security, positioning flexibility and accuracy, versatility, and solve the problem of user authentication [1]. Among indoor positioning technologies, Ultra wide band (UWB) can achieve centimetre-level positioning accuracy by transmitting extremely short pulse signals for data transmission, with pulse widths usually at the nanosecond level. This characteristic makes UWB technology featured with high bandwidth, high data transmission rate and low power consumption, and at the same time, it can achieve high accuracy positioning. In this paper, based on UWB technology, combined with the MCU (micro control unit) main control core, a smart door lock system integrating high-precision positioning, automatic unlocking and cloud security functions is designed. The system contains three beacons (beacon embedded in the door lock, beacon outside the door, and user beacon), and uses the bilateral two-way ranging (DS- TWR) algorithm to achieve accurate positioning of the user near the door, and then detects the user's movement status through continuous ranging to achieve the automatic unlocking function of the door lock under specific conditions. By embedding the camera inside the door lock, the portrait information is detected and compared to monitor the abnormal data, and the One Net cloud-based server is used so that the security data can be transmitted between the client and the smart door lock to achieve the function of remote data transmission and remote control.