Security is a prime concern in our day-today life. Everyone wants to be as much secured as possible. Keypad based password is one of the many method and the most common and easy one to provide security to any system.
In this project, we will learn How to design a password protected system using a 4X4 keypad with AVR ATmega16 microcontroller. Here, the user will enter a 4 digit numeric password to gain access of the system and after gaining access of the system, the user presses different keys of the 4X4 keypad and the system displays the value of the pressed key in a 1X8 LED array. The user enters the 4 digit numeric password by pressing different keys of the 4X4 keypad one by one. For each key pressed all the 8 LEDs of the 1X8 LED array will be ON for 500ms to indicate that a digit of the password has been entered. After entering 4 digits of the password, the microcontroller compares the entered password with the set password (1234 in our case) and displays the result of the comparison in the 1X8 LED array as upper 4 LEDs of the 1X8 LED array are ON for correct password or lower 4 LEDs of the 1X8 LED array are ON for wrong password. Once the correct password is entered, the user can press different keys of the 4X4 keypad and the 1X8 LED array displays the value of the pressed keys. Try entering different combinations of passwords and see the output.
| Key Pressed | Key Value |
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
| 5 | 5 |
| 6 | 6 |
| 7 | 7 |
| 8 | 8 |
| 9 | 9 |
| * | 10 |
| # | 11 |
| A | 12 |
| B | 13 |
| C | 14 |
| D | 15 |
Softwares Required
Hardwares Required
| Name | Quantity |
 AVR Trainer Board-100 with ATmega16 |
1pc |
 AVR USB Programmer |
1pc |
 12V, 1A DC SMPS Adaptor |
1pc |
 4X4 Keypad |
1pc |
 10 to 10 FRC Female to Female Connector |
1pc |
Read more: 4X4 Keypad based Password with ATmega16 and LED Display