To secure a room in my house, I made a door lock system using two Arduino microcontrollers, an RFID scanner, and a stepper motor. One Arduino microcontroller serves as a display outside the room, connected to an LCD to show status messages and an RFID scanner to read key cards/fobs. Another Arduino is placed inside the room, connected to an LCD status display, a stepper motor to control the door lock, and a computer to manage the lock’s modes.
I programmed the Arduinos using C++. When a card is presented to the outside Arduino, it first checks the card’s ID against a set of pre-programmed valid IDs. If it matches, it displays a success message on its LCD and sends a signal over serial to the inside Arduino, which tells it to turn the stepper motor and unlock the door.
Modes#
The current state of the door lock is displayed on both LCDs. This can be changed by entering a PIN on the computer connected to the inside Arduino.
- Default: In this state, the door is locked until a valid card is presented to the RFID scanner.
- Unlocked: In this state, the door remains unlocked, and a card is not required.
- Locked: In this state, the door is always locked, and card reading is disabled.