RFID Readers

Type 2 tags are better and are used by smartphones

LF Readers

  • made with a coil for signal generation
  • Options
    • RDM6300
    • RDM634

HF Readers - made with antenna embedded into pcb - Options - MFRC-522 - Contains user changable code

UID

Wiegand is protocol to connect reader to controller

Two Formats

  • W26
  • W34 (longer, preferable)

Output Signal

LF - See a spike in frequency domain in 125 khz - Might see the harmonics later if designed cheaply without filters

When placed next to RF tag, signal gets smaller because it powers tag and spectrum gets wider (signal is modulated)

Reach

  • 2.5 cm for a tag
  • 4 cm for a card (bigger card antenna)
  • For LF, the sheilding has no real affect
  • But if you put 2 different cards next to each other, signal is muffled

Encryption

Sophisticated encrypted systems - MIFARE DESFire - HID iClass

Build your own

  • RDM6300
  • connect to a software serial
  • to arduino uno

Duplication Notes:

  • Encrypted or proprietary RFID technology for security purposes (encryption or rolling codes)
  • Standard, unencrypted tags (like low-frequency or high-frequency RFID tags) can be copied easily