# RfidResearchGroup/ChameleonUltra

The new generation chameleon based on NRF52840 makes the performance of card emulation more stable. And gave the chameleon the ability to read, write, and decrypt cards.

Repository: https://github.com/RfidResearchGroup/ChameleonUltra
Canonical: https://ross.abutalabs.com/products/chameleonultra
Language: C
License: GPL-3.0
License Family: copyleft
Topics: 125khz, chameleon, iso14443a, mifare, nfc, ntag, rfid, simulate, ultralight, chameleonultra, detection
Last push: 2026-08-10T20:51:58+00:00

## Health v2 (maintenance only)
Score: 84/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 97, release rhythm 59, longevity 96
- inputs: {"age_days": 1350, "days_push": 23, "days_rel": 60, "gap_med": 304, "n_releases_24m": 2}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2949, forks 433 (observed 2026-08-28T04:07:31.893743+00:00)

## What it is
ChameleonUltra is the open-source firmware for an RFID/NFC card emulation device based on the NRF52840, capable of reading, writing, decrypting, and simulating cards like Mifare and NTAG. It is controlled via a CLI and companion GUI apps over BLE.

## Use cases
- emulate mifare classic cards
- clone rfid access cards
- read and decrypt nfc tags
- simulate 125khz and 13.56mhz cards
- test nfc readers with card emulation
- analyze iso14443a card communication

## When to choose
- you own a Chameleon Ultra device and need firmware or client tooling
- you need a programmable RFID/NFC card emulator for security research
- you want to clone or emulate Mifare, NTAG, or 125kHz credentials

## When to avoid
- you need software-only NFC emulation without dedicated hardware
- you want a general-purpose SDR or smart-card tool outside RFID/NFC
- you need a turnkey commercial product rather than a research device

## Facets
- artifact type: application
- maturity: active
- function: security, cli, developer-tools
- domain: security, hardware, reverse-engineering
- platform: embedded, cross-platform, cli
- tags: rfid, nfc, mifare, card-emulation, firmware, nrf52840, 125khz, iso14443a

## Member repositories
- RfidResearchGroup/ChameleonUltra (main) score 84

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:31.893743+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 2026-08-30T07:32:43.901011+00:00, confidence not recorded.
  - readme: https://github.com/RfidResearchGroup/ChameleonUltra (fetched 2026-08-28T04:07:31.893743+00:00, sha a0b7dbe26e52)
- Data as of 2026-08-30T08:39:29.467469+00:00.