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nfc-hardware-research

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NFC Hardware Research

Research notes from evaluating NFC readers and cards for the guild check-in kiosk.

Key Concepts

  • RFID is the broad category. NFC is a subset operating at 13.56 MHz (HF).
  • iPhones only support 13.56 MHz NFC — no LF (125 kHz) or UHF (860-960 MHz).
  • NFC tags have a factory-burned UID (unique identifier) that cannot be changed. This is what we use to identify members — no data is written to the card.
  • Reading distance for USB NFC readers is typically 0-70mm depending on tag type.

Readers Evaluated

ACS WalletMate II (ACR1552U-MW) — CHOSEN

  • Spec sheet: TSP-WalletMate-II-1.03.pdf (Feb 2025)
  • Apple VAS & Google Smart Tap certified (ECP 1.0 & 2.0)
  • Supported cards: ISO 14443 A&B Parts 1-4, ISO 15693, ISO 18092 NFC, MIFARE Classic/Ultralight/DESFire/Plus, FeliCa, SRI/SRIX, CTS, Innovatron, Picopass, Topaz
  • 13.56 MHz, read distance up to 70mm
  • Read/write: 106/212/424/848 kbps (ISO 14443), 26 kbps (ISO 15693)
  • USB Type-A, CCID & PC/SC, 5VDC, 300mA max
  • NFC modes: Reader/Writer, Keyboard Emulation, Card Emulation
  • SAM slot (ISO 7816 Class A)
  • LTPK stored in secure element for Apple VAS / Google Smart Tap
  • Programmable buzzer + LED (blue & green)
  • Linux/Windows/macOS/Android support
  • 98 x 65 x 12.8mm, 86g, white

ACS ACR1252U — CONSIDERED

  • Spec sheet: TSP-ACR1252U-2.02.pdf (March 2024)
  • NFC Forum Certified, no wallet pass support
  • Supported cards: ISO 14443 A&B, ISO 18092, MIFARE, FeliCa
  • 13.56 MHz, read distance up to 50mm
  • Read/write: 106/212/424 kbps (programmable)
  • Available in USB Type-A (ACR1252U-M1) or USB-C (ACR1252U-MF)
  • NFC modes: Reader/Writer, Peer-to-Peer, Card Emulation
  • SAM slot, programmable buzzer + LED (red & green)
  • CT-API library, SDK available ($149)
  • 98 x 65 x 12.8mm, 81g, matte black

ACS ACR122U — REJECTED

  • EOL since 2018, no longer recommended

Why WalletMate II over ACR1252U

Same physical form factor. WalletMate II is a superset: wider card protocol support, faster read speed (848 vs 424 kbps), longer read distance (70 vs 50mm), and Apple VAS + Google Smart Tap certification. Costs more but future-proofs for phone-based check-in without a hardware swap.

Cards Chosen

  • NTAG215 — ISO 14443A, 13.56 MHz, 504 bytes, 100k write endurance
  • Form factor: PVC cards (credit card size)
  • UID is factory-burned and unique per card
  • Personalization plan: matte black cards, hand-lettered with gold Posca paint markers, sealed with UV resin topcoat

Prototyping

  • Flipper Zero (already owned) can read NTAG215 UIDs for testing before WalletMate arrives
  • Flipper is handheld, not USB — read UIDs from its screen and test the check-in API manually

iPhone NFC Limitations (from rfidlabel.com research)

  • iPhone NFC only does 13.56 MHz (HF) — no LF or UHF
  • Read range: 0-10cm
  • Cannot do multi-tag simultaneous reading
  • Cannot emulate older non-NFC RFID access cards
  • Write limited to NFC Forum-compliant tags
  • For phone-as-card: requires Apple Wallet pass provisioning (PassKit + Apple Developer entitlement)

Graph View

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