Electronic security code lock system

Hardware configuration:
- 16 x 2 LCD user interface
- 4 x 3 keypad for user password entry with 0-9,* #
- Stepper motor for lock/unlock operation
- Choice of relay, servo motor, DC motor or electromagnetic
- There is a traffic light indicator signal
- If the door is locked, the red light is on; if the door is unlocked, the green light is on
- The buzzer indicates the correct/error status.

User operations:
- The initial password is 1234, the user can change the new password
- Enter the correct password to unlock
- the system A prompt will be given for each incorrect operation 
- only the correct password will unlock the door

- Users can change their password by entering 9999

- This will require the current password

- If there is no problem, enter the new password
- The user only needs to press the "*" key to lock the door and

run silently:
- When the system starts, the stepper motor will find the home position through the lever switch
- Input will be obtained from the switch outside
- When input is received, the location of the home is confirmed
- The door to the home is locked
- The stepper motor is released (off state) after each operation
- This operation saves power
- The password is stored in the microcontroller memory
- In the off condition, the circuit will remember the password without the need for any backup battery
- when unlocking the door, the user will press the "*" key and an unlocked message will be sent

• Chapter 1：Electronic security code lock system (3 minutes and 48 seconds)