SIMS: Smart Inventory Management System

1. SIMS:Smart Inventory Management System Group 37 Masaki Negishi & Anthony Fai ECE 445 Senior Design April 27, 2005

2. 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

3. Features • PC serial interface • Compatible with RFID Readers and Antennas • Up to 8 outputs per unit • Expandable, modular design

4. The SIMS System

5. 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

6. System Overview

7. 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

8. PC Interface Processing Unit • PIC Microprocessor • RS232 Serial Communication with PC • Sends output to RF Switching Unit

9. Thin colors will not have good contrast on a projector PC Interface Processing Unit (Schematic)

10. RF Switching Unit • Takes in input from RFID reader • Four outputs per board (expandable) • Relay switching

11. RF Switching Unit (Schematic)

12. 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

13. 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

14. Thin colors will not have good contrast on a projector Power Supply (Schematic)

15. Hardware Overview (Outsourced) • TI RFID S6500 HF Reader • TI RFID HF Transponders • TI RFID HF 13.56 MHz Antenna (RI-ANT-T01A)

16. 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

17. 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

18. Factors Influencing Communication with Tags • Orientation of tag with respect to antenna • Environment around tag (e.g. metals, liquids) • Background Noise

19. Recommendations for Tag Placements • Parallel to antenna • Away from metals • Within reading range of antenna (~25 cm)

20. 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

21. 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)

22. Thin colors will not have good contrast on a projector Loop Antenna (Self-Made) • Measurement Results (SWR = 60.832)

23. Loop Antenna (RI-ANT-T01A) • Dimension: 337mm x 322mm x 38mm • Matched to 50 Ohms • Maximum Reading Range: 50cm

24. Thin colors will not have good contrast on a projector Loop Antenna (RI-ANT-T01A) • Measurement Results 1: Vertical, Away from Metal • SWR = 1.004

25. Thin colors will not have good contrast on a projector Loop Antenna (RI-ANT-T01A) • Measurement Results 2: Horizontal, Sitting on Lab Table • SWR = 1.636

26. Thin colors will not have good contrast on a projector Loop Antenna (RI-ANT-T01A) • Measurement Results 3: Close to Lab Equipments • SWR = 5.111

27. Thin colors will not have good contrast on a projector Overall Z-Parameters • SIMS System + Antenna Results During Operation • SWR = 1.349

28. Factors Influencing Antenna Impedance • Orientation • Environment (e.g. metals, liquids) • Noise • Antenna is operating always in near field since wavelength is 22 meters!

29. Too must text on this slide Antenna Recommendations • The antennae must be placed first, and then must be tuned to the correct frequency. • May need multiple antennae at one station for more complete coverage (this would help avoid nulls from environmental factors) • Will need a larger antennae to achieve a longer reading range • We do notcompletely trust the antenna cookbooks because they are unreliable! • We suggest buying one antenna first, then analyze it and make sure it meets your specifications.

30. 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

31. 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

32. Please do not include blocks of code. Small amounts of pseudo code is just fine. PIC Software • Switch0331.hex – example code use Win32::SerialPort; my $com_port1 = new Win32::SerialPort ("COM1"); die "Can't open serial port COM1: $^E\n" unless ($com_port1); $com_port1->baudrate("9600"); $com_port1->databits("8"); $com_port1->stopbits("1"); $com_port1->parity("none"); $com_port1->handshake("none"); $com_port1->write_settings || die "\nUnable to write settings for COM1"; my ($in1_count, $in1_string) = $com_port1->read(1); # read 1 byte if ($in1_string ne '') { my $temp = Ascii2Hex($in1_string); print "\nCOM1 Input: $in1_string : 0x$temp ($in1_count bytes)\n"; } print "\nCOM1 - Data to Send in Hex (default: $data): 0x"; my $tmp = <STDIN>; chomp $tmp; $data = $tmp; my $temp = Hex2Ascii($data); my $count_out = $com_port1->write($data); print "COM1 Output: $temp : 0x$data ($count_out bytes)\n";

33. Room Setup • Map out room and give coordinates to each antenna • For example, antenna B-2 can correspond to the secretary’s desk

34. 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

35. Future Software Development • Friendly user online interface (HTML) • Information processing on transponder data • Network with central server

36. RFID Frequency Comparison

37. SWOT Analysis of SIMS

38. Credits • Mr. Richard Martin Cantzler, II • Professor P. Scott Carney • Mr. Nicholas Soldner • Professor Jennifer T. Bernhard • Professor Steven J. Franke

39. Thank You