# miguelbalboa/rfid

Arduino RFID Library for MFRC522

Repository: https://github.com/miguelbalboa/rfid
Canonical: https://ross.abutalabs.com/products/rfid
Language: C++
License: Unlicense
License Family: permissive
Last push: 2026-07-02T14:30:34+00:00

## Health v2 (maintenance only)
Score: 63/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 90, release rhythm 8, longevity 100
- inputs: {"age_days": 5106, "days_push": 62, "days_rel": 562, "gap_med": null, "n_releases_24m": 1}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3033, forks 1493 (observed 2026-08-28T04:07:38.999616+00:00)

## What it is
An Arduino library for driving MFRC522-based RFID reader modules over SPI, supporting reading and writing MIFARE Classic and related cards. Development is frozen; the maintainer recommends the successor Arduino_MFRC522v2 library for new work.

## Use cases
- read RFID card UIDs with an Arduino
- write data to MIFARE Classic 1K/4K card sectors
- build an RFID door lock or access control project
- change the UID on Chinese UID-changeable MIFARE cards
- interface an RC522 module over SPI with Arduino
- run the MFRC522 firmware self-check to detect fake boards

## When to choose
- you have an MFRC522/RC522 module and an Arduino and need mature, widely-documented example code
- your project depends on the classic API that many existing tutorials and projects use
- you need MIFARE Classic Crypto1 communication or UID writing

## When to avoid
- starting a new project - use the successor Arduino_MFRC522v2 library instead
- you need MIFARE DESFire, 3DES, or AES support, which is not implemented
- you need support for boards other than Arduino or new features - development is frozen

## Facets
- artifact type: library
- maturity: maintenance
- function: embedded, sdk
- domain: embedded-systems, hardware, iot
- platform: embedded, cpp, c
- tags: arduino, rfid, mfrc522, spi, mifare, nfc

## Member repositories
- miguelbalboa/rfid (main) score 63

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:38.999616+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T07:29:47.212989+00:00, confidence not recorded.
  - readme: https://github.com/miguelbalboa/rfid (fetched 2026-08-28T04:07:38.999616+00:00, sha 6eab75209542)
- Data as of 2026-08-30T08:39:29.467469+00:00.