Code Lock Based on AVR Microcontroller

The Atmel AVR microcontroller ATtiny2313 or AT90S2313 is used to build an electronic combination lock known as Code Lock, which will be used for access control.

The user code in this device consisted of 1 to 4 digits and can be consisted of 1 to 8 digits if the chip is bought than the user code. The relay and the electric door striker will switch ON for 1 second and then switch OFF again after 1 second of entering the code in the correct sequence. Using the 3×4 matrix keypad, the user code can be changed. This keypad can be purchased at a local electronic shop.

By setting up the keypad with a jumper, the initial user code is 1234 and before the 12V connection, the jumper must be inserted. It must be removed after 2 beeps or 5-15 seconds. With one short beep, the immediate pressing of each key is confirmed. After entering the right user code, two short beeps will follow. When the wrong user code is entered, one long beep will appear. For each incorrect action, the keypad is blocked for 20 seconds. A LED can replace the beeper.

Rest of the project