Electronic Letter Box project is developed for the users to find out whether any letter is inside the letter box and also to display the number of letters inside the letter box.
An IR Transmitter and Receiver are connected at the opening of the letter box. In normal operation, the rays transmitted from the transmitter falls on the receiver.
When anyone puts letter inside the letter box, the letter hides the rays and thereby the receives no signal at the particular instance. Thus it senses that there is a letter inside.
The microcontroller connected with the sensor counts that there is one letter inside. When the next letter is put inside the letter box, the sensor senses the letter and the microcontroller counts two. The same way it counts all the letters inside.
A display and buzzer is connected inside the house. The owner of the house can identify the number of letters inside the letter box.
When the letter box is opened, the microcontroller resets and the count goes to zero