Door Messaging System was our first project. It all started here! We worked under Prof. Anshul Kumar at the Digital Hardware Design lab of IIT, Delhi. Our objective was to make an embedded, menu driven door messaging system – that allows users to store and retrieve messages.

Essential Features:

1. The system is accessible in 2 modes – Guest and Administrator.
2. When accessed as a Guest, the name and message is accepted and stored.
3. When accessed in the password protected Administrator mode the user is able to retrieve the messages.
4. It is a user friendly menu-driven interface.
5. The input device is a switch-based keypad and the output is displayed on a 2x16 LCD display.

To achieve the aforementioned features, ATMega8 had to be interfaced with:

1. 1024x8 bit NV-RAM (Non-Volatile RAM).
2. 2x16 LCD display
3. Switch-based keypad (16 push button switches)

The software and hardware implementation had to be such that the port pins of ATMega8 are optimally utilized to integrate these peripherals without any data contention or conflict. A common 8 bit data bus interacted with the keypad, the LCD and the memory. Here is a report.