SIMS: Smart Inventory Management System Group 37 Masaki Negishi & Anthony Fai ECE 445 Senior Design April 27, 2005
Dec 15, 2015
SIMS: Smart Inventory Management
System
Group 37Masaki Negishi & Anthony Fai
ECE 445 Senior DesignApril 27, 2005
Introduction SIMS provides a cost effective
solution for the management of inventory which leverages RFID technology.
Combines an antenna array to a single RFID reader to map out an area for inventory detection
Features PC serial interface Compatible with RFID Readers and
Antennas Up to 8 outputs per unit Expandable, modular design
The SIMS System
The images in this presentation have been reduced to screen quality (saves space)
Format Picture -> Compress
System Overview Hardware:
Power Supply, PC Interface Processing Unit, RF Switching Unit
TI HF RFID Reader, TI HF RFID Antenna, TI HF RFID Transponders
Software: PC control for antenna switching
System Overview
Hardware Overview (In House Manufactured) Power Supply
Takes 6Vdc from AC/DC wall converter and converts to stable 5Vdc
PC Interface Processing Unit PC communication with system
RF Switching Unit Switching of RF signal from reader to
selected antenna
PC Interface Processing Unit PIC
Microprocessor RS232 Serial
Communication with PC
Sends output to RF Switching Unit
PC Interface Processing Unit (Schematic)
Black will have better contrast on a projector
RF Switching Unit Takes in input
from RFID reader Four outputs per
board (expandable)
Relay switching
RF Switching Unit (Schematic)
5Vdc
Input from PIC
RF OUTPUT TO PIC
RF input from Reader
Normally Open SPDT RelaySwitch
PIN Diode Switching Unit (Eliminated) Employ PIN Diodes for Switching Great performance for small peak to
peak AC signal (low power) Poor performance for large peak to
peak AC signal (high power) Introduce impedance mismatch
Power Supply (Main Idea)
Supplies +5 Vdc and GND to switch and control units
Maximum current: 1A
More stable compared to 5V from the wall
Power Supply (Schematic)
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Power Supply (Results)
Vmax: 5.023 V Vmin: 4.975 V Max. Ripple:
48.44mV Freqnency:
95.057KHz
We always like to see measured data (especially with waveforms)!
Hardware Overview (Outsourced) TI RFID S6500 HF Reader TI RFID HF Transponders TI RFID HF 13.56 MHz Antenna
(RI-ANT-T01A)
TI RFID S6500 HF Reader RFID Reader
Necessary to read and write to transponders
Can be connected to PC through RS232
Operating Frequency of 13.56 MHz (HF)
Output voltage of 48 V peak-to-peak
Power output of 4 W
TI RFID HF Transponders
Transponders Receives
13.56MHz of the signal from the reader, and sends back a signal to the reader
Consists of a loop antenna and a chip microprocessor
Factors Influencing Communication with Tags
Orientation of tag with respect to antenna Environment around tag (e.g. metals, liquids) Background Noise
Recommendations for Tag Placements Parallel to antenna Away from metals Within reading range of antenna (~25
cm)
TI RFID HF 13.56 MHz Antenna
Used to transmit and receive signals.
Used for Magnetic
Tuned at 13.56 MHz
Input Impedance of 50 Ohms
Loop Antenna (In House) Followed Texas
Instruments’ Antenna Cookbook
50cm x 50cm Made of copper tape
and wooden board T-matching network Reading range of 1
mm (SWR ~ 2.2)
Loop Antenna (Self-Made) Measurement Results (SWR = 60.832)
Black will have better contrast on a projector
Loop Antenna (RI-ANT-T01A)
Dimension: 337mm x 322mm x 38mm
Matched to 50 Ohms
Maximum Reading Range: 50cm
Loop Antenna (RI-ANT-T01A)
Measurement Results 1: Vertical, Away from Metal SWR = 1.004
Black will have better contrast on a projector
Loop Antenna (RI-ANT-T01A)
Measurement Results 2: Horizontal, Sitting on Lab Table SWR = 1.636
Black will have better contrast on a projector
Loop Antenna (RI-ANT-T01A)
Measurement Results 3: Close to Lab Equipments SWR = 5.111
Black will have better contrast on a projector
Overall Z-Parameters SIMS System + Antenna Results During Operation
SWR = 1.349
Black will have better contrast on a projector
Factors Influencing Antenna Impedance Orientation Environment (e.g. metals, liquids) Noise
Antenna is operating always in near field since wavelength is 22 meters!
Antenna Recommendations
Antennae must be placed first, then tuned. May need multiple antennae at one station
for more complete coverage (and avoid nulls from environmental factors)
Larger antennae for longer reading range Do not completely trust antenna
cookbooks because they are unreliable! Buy one antenna first and analyze it.
Just about the maximum amount of text on a slide
Software PERL software
Takes in user input and sends out two HEX digits through RS232 serial port (I/O)
PIC software Takes in input from RS232 serial port and
sends logic high to corresponding pins
PERL Software Serial.pl
Takes in keyboard inputs in HEX Must read header “AF” followed by two HEX
digits (e.g. AF06) Send out input from COM 2 to PIC Checks to see if PIC received correct signal
PIC Software Switch0331.hex
Takes input from RS232 and sends logic high to corresponding outputs
Will only respond if header “AF” is seen Sends back to PC its output
Room Setup Map out room and
give coordinates to each antenna
For example, antenna B-2 can correspond to the secretary’s desk
Future Hardware Development Improved Switching Unit for longer
lifetime and higher signal isolation Increased number of antenna outputs Improved Antenna Design
Larger loop antenna More stable impedance matching network
and BALUN
Future Software Development Friendly user
online interface (HTML)
Information processing on transponder data
Network with central server
Workstation
Server
Laptops
Workstation Workstation
Workstation
RFID Frequency Comparison
Frequency Pros ConsLF (100 – 140KHz; ~2.5 km)Read Range: ~100 cm MAXMagneticInductive Transponders
Less susceptible to environmentLonger reading range than HF
Only usually one transponder can be read at a time Tags bulkier and more expensive than HF ones and less memory capacity
HF (13.56MHz; ~22m)Read Range: ~50 cm MAX (current antenna ~25 cm)MagneticInductive Transponders
Anti-collision intelligence allows multiple of tags to operate concurrentlyWell defined magnetic field
More susceptible to environmentShort reading range
UHF (860 – 960MHz; ~33 cm)Read Range: ~9m MAXElectric (but passive tags)Capacitive Transponders
Anti-collision detectionLong reading range
Not well defined electric fieldField nulls near antenna requires complex anti-collision intelligenceTags have less memory capacity
SWOT Analysis of SIMS
Strengths:Modular designSupports LF and UHFMinimize number of readersCost effective
Weakness:Short rangeSusceptible to environmental factorsRelay power consumption and lifetime
Threats:Smart ShelvesRTLS
Opportunities:Inventory ManagementUHF implementationSoftware Expansion
Credits Mr. Richard Martin Cantzler, II Professor P. Scott Carney Mr. Nicholas Soldner Professor Jennifer T. Bernhard Professor Steven J. Franke
Thank You