This Smart Door Lock project uses a micro:bit, relay, solenoid, and RFID system to create an automatic and secure door access solution. The RFID reader detects an authorized card, then the micro:bit processes the input and activates the relay. The relay allows current to flow to the solenoid, unlocking the door. If the card is not recognized, the door remains locked. This system offers a simple, efficient, and modern alternative to traditional keys.