This project is to design a lock-system using password. In the design, there will be a keypad in order to type the password. The keypad was designed using voltage, resistors, and push buttons. Meaning, all the previous components will be connected together so that each push buttons will have unique voltage that is derived from using voltage divider rule. Also, there will be an LCD that will show what was typed in the keypad. If the password is correct, then a successful message will be displayed on the LCD and then the system will be unlocked. Otherwise, the system will be locked. And if the password was entered is not correct then denial message will be displayed and the system will not be unlocked.
How the design works:
When the design is powered up, RB0, which is the simulated system that is denoted by LEDs (Red and Green), will be zero. So, the Red LED will be on and the Green LED will be off. Also, there will be a message “Enter password:” that is displayed in the LCD. If any push button is pressed, the corresponding number will be displayed on the LCD. The password is consisting of 4 numbers. In this design the password is 1111. Thus, when 4 numbers are typed, the microcontroller will check the typed password with 1111. If the typed password was correct, then a message “Access granted” will be displayed in the LCD and the Green LED will be on and the Red LED will be off for few second then the system will be locked and ask for password. If the password is not correct, then a message “Access denied” will be displayed in the LCD and the Red LED will be on and the Green LED will be off.
The Simulation on Proteus: