While travelling in public transport such as buses or trains, people usually carry expensive belongings and are quite insecure about their safety. Even though after [[wysiwyg_imageupload::]]locking the luggage thoroughly, there is always a worry about it.To solve this problem here is a simple circuit based on NAND gate. When somebody tries to steal the luggage, the circuit will give a warning alarm. An audio visual indication can also be provided by connecting it to the relay.This project circuit can also be used in home to prevent the attempt of burglary as when somebody tries to open the door, the loop breaks and the alarm. The project is built around CD4011 with components like LDR, variable resistor, capacitor, transistor and relay.. It generates a warning beep when somebody attempts to open the locker.