The ‘Smart Mail Box’ project aims to let users know the existence of letters in their mailboxes. The project will generate a sound signal immediately when the letter is entered in the mailbox. With this project the user does not have to bother to check the mailbox every day. The project consists of 2 circuits, the ‘ LDR Sensor’ and the Motor DC with Bluetooth Module. The LDR circuit is used as a light sensor in the letterbox because when the letter is inserted the light that is displayed on the circuit will be blocked and the signal will be given to the LDR circuit to produce a sound through the buzzer. The Motor DC circuit is used to control the mailbox with Bluetooth applying on a mobile phone. The time taken for their whole circuit is within 4 month. This is because the first, second and third attempts fail because the circuit is not working properly. Using Proteus 8 to create a schematic circuit and see the function of the circuit. After that, use the project board as the first step for circuit testing. After working, use the Printed Circuit Board (PCB) as the next step. While in the process of setting up the circuit, the former to place the circuit is also set up like a letterbox and a robot to control the mailbox.