Vincent Piziali, Robert Sebastian, Pavan Bhatia, Callie Jacobs,

1
RFID DOOR UNLOCKING SYSTEM
Vincent Piziali, Robert Sebastian, Pavan Bhatia,
Callie Jacobs, He(Damon) Li, and Matthew Hayes
vxp036000_at_utdallas.edu, ras033100_at_utdallas.edu,
pkb033000_at_utdallas.edu, crj031000_at_utdallas.edu,
mjh045000_at_utdallas.edu hxl043100_at_utdallas.edu
Department of Electrical Engineering Erik Jonsson
School of Engineering Computer
Science University of Texas at Dallas Richardson,
Texas 75083-0688, U.S.A.
Project Results
Project Goals

• Receiver output without presence of tag
• Receiver output with presence of tag

• Design an EAS-like RFID enabled unlocking system
  for pet door to provide protection from entrance
  of unwanted animals into the home
• Detect the presence of an RFID tag at a specified
  frequency
• Send signal to unlock servo-controlled door lock

Project Overview

• Transmitter/VCO Voltage-controlled ring
  oscillator takes input from microcontroller and
  sets an output frequency of 13.36MHz - 13.56MHz.
  The square wave signal is buffered and filtered
  to produce a sine wave, which is amplified to a
  /-15V output signal with a class-B amplifier.
  This is output into a loop antenna.
• Receiver A smaller loop antenna receives the
  transmitted signal plus a small signal in the
  opposite direction reflected by the tag. This
  results in a small dip in the amplitude of the
  response. The receiver amplifies the amplitude
  of this signal and feeds it to the
  microcontroller, which does the detection.
• Microcontroller Software controls the frequency
  sweep, detects the presence of the tag by reading
  the response signal amplitude after each sweep
  point. Provides system status information via
  LEDs.

Transmitter
Project Conclusions/Outcomes

• Completed planning of overall system
• Designed and built individual system components
  Receiver, transmitter, VCO, power supply, and
  servo-controlling PWM
• Successfully integrated system components to
  detect presence of
• RFID tag at 13.56MHz and to lock/unlock the door
  depending on the tags presence
• Learned to work in a team environment

Receiver
PWM
Power Supply