Everyday technological advancement and expansion make safety more and more crucial across all fields. Everybody wants a private space that only they can access, so one must secure the room, office, locker, and other space that protect the priceless jewelry, documents, and accessories. To that end, the chapter has created a knocking sensor-based door lock system by using Arduino. A sensor-based door opening and closing system has been designed to enable the opening and closing of the door. A project on Arduino UNO has been made to detect the knocking at door. Depending on the number and time interval of knocks, the sensor detects, and a signal is generated which lights the LED and displays information on LCD. The system is designed to provide the safety of a person. The future scope of the design is to implement it with IoT-enabled devices.