RFID Pet Door Opener using Arduino

Pet doors are convenient and insecure in equal measure: a basic flap lets in any animal — and through a large flap, an intruder's hand. RFID access control solves the pet side of that problem the same way it secures office doors: only a registered credential opens the way. This project builds that idea with commodity parts. An Arduino Uno continuously polls an RC522 13.56 MHz RFID reader; when a tag is presented, its UID is compared against a registered list stored in the Arduino's EEPROM. A match drives an SG90 servo to swing the model door's flap open for a configurable hold time, then closes it; an unknown tag is simply ignored. Enrolling a new tag needs no PC — a documented button sequence puts the unit in enroll mode and the next presented tag is stored. The prototype is built at model scale on a wooden door frame, which keeps every mechanism visible and explainable for the report and viva. This is a built-to-order hardware project: the prototype is assembled, wired and tested fresh for your order.

1. The RC522 reader continuously polls for 13.56 MHz tags within a few centimeters.
2. When a tag is presented, the Arduino reads its UID over SPI.
3. The UID is compared against the registered list stored in the Arduino's EEPROM.
4. On a match, the SG90 servo rotates to swing the flap open; after the configured hold time it rotates back and the door closes.
5. An unknown UID is ignored — the flap never moves — so unregistered animals (or tags) stay outside.
6. Enrollment: a documented button sequence enters enroll mode, and the next presented tag's UID is written to EEPROM.

Tech stack:

• Arduino Uno R3 (ATmega328P)
• RC522 RFID reader module (13.56 MHz)
• SG90 micro servo motor
• MIFARE key fobs / cards (registered tags)
• Arduino IDE + MFRC522 library
• 5 V USB power supply
• Model wooden pet-door frame with flap

• [Tag-based access] Only registered MIFARE tag UIDs actuate the door; unknown tags are ignored and the flap stays shut.
• [Servo door actuation] An SG90 servo swings the flap open on a valid scan and returns it after a configurable hold time.
• [PC-free enrollment] New tags are registered with a documented button procedure and stored in EEPROM — no computer needed after setup.
• [Adjustable hold time] The open duration is a single firmware constant, tunable to the pet and door.
• [UID registry in EEPROM] Registered tags survive power cycles without re-enrollment.
• [Fully offline operation] No Wi-Fi, no cloud, no app — the entire access decision happens on the Arduino.

• Assembled and tested working prototype (Uno, RC522, SG90, model door frame)
• Complete firmware source code (reading, UID matching, servo control, enrollment)
• Circuit/wiring documentation with connection diagram
• Component list with sourcing notes
• Tag enrollment and testing procedure
• Project report PDF (background, methodology, test table of tag trials)
• PPT presentation for final review
• Viva Q&A preparation document (RFID, SPI, EEPROM, servo control)

• The RC522's design-target read distance is only 2–5 cm — the tag must be presented close to the reader, which suits a pet collar tag but not walk-up detection.
• UID-only checking is not strong security: MIFARE Classic UIDs can be cloned, so this is pet convenience, not a high-security lock — the report states this openly.
• The SG90's ~1.8 kg·cm torque lifts the light model flap only; a real door needs a larger actuator (documented as future scope).
• The prototype is a model-scale demonstrator on a wooden frame, not a weatherproof installed pet door.
• EEPROM has limited write cycles (~100,000); enrollment is infrequent by design.