RFID reader documentation

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Parallax, Inc. • RFID Reader Module (#28140) •Updated 09/2005 v1.1 Page 1

599 Menlo Drive, Suite 100

Rocklin, California 95765, USA

Office: (916) 624-8333

Fax: (916) 624-8003

General: info@parallax.com

Technical: support@parallax.com

Web Site: www.parallax.com

Educational: www.stampsinclass.com

RFID Reader Module (#28140)

RFID 54 mm x 85 mm Rectangle Tag (#28141)

RFID 50 mm Round Tag (#28142)

VCC

SOUT

/ENABLE

GND

idea studio

2.45” (62.2mm)

3.25” (82.5mm)

2.15” (54.5mm)

0.1” (2.5mm)

2.95” (75mm)

0.14” (3.6mm)

Introduction

Designed in cooperation with Grand Idea Studio (http://www.grandideastudio.com/), the Parallax Radio

Frequency Identification (RFID) Reader Module is the first low-cost solution to read passive RFID

transponder tags up to 1 ¾” - 3” inches away depending on the tag (see list below). The RFID Reader

Module can be used in a wide variety of hobbyist and commercial applications, including access control,

automatic identification, robotics navigation, inventory tracking, payment systems, and car

immobilization.

• Fully-integrated, low-cost method of reading passive RFID transponder tags

• 1-wire, 2400 baud Serial TTL interface to PC, BASIC Stamp

and other processors

• Requires single +5VDC supply

• Bi-color LED for visual indication of activity

• 0.100” pin spacing for easy prototyping and integration

Summary of content (10 pages)

PAGE 1
599 Menlo Drive, Suite 100 Rocklin, California 95765, USA Office: (916) 624-8333 Fax: (916) 624-8003 General: info@parallax.com Technical: support@parallax.com Web Site: www.parallax.com Educational: www.stampsinclass.com RFID Reader Module (#28140) RFID 54 mm x 85 mm Rectangle Tag (#28141) RFID 50 mm Round Tag (#28142) 2.45” (62.2mm) 3.25” (82.5mm) VCC /ENABLE SOUT GND idea studio 2.95” (75mm) 2.15” (54.5mm) 0.14” (3.6mm) 0.1” (2.
PAGE 2
The Parallax RFID Reader Module works exclusively with the EM Microelectronics-Marin SA EM4100-family of passive read-only transponder tags. A variety of different tag types and styles exist with the most popular made available from Parallax. Each transponder tag contains a unique identifier (one of 240, or 1,099,511,627,776, possible combinations) that is read by the RFID Reader Module and transmitted to the host via a simple serial interface.
PAGE 3
Communication Protocol Implementation and usage of the RFID Reader Module is straightforward. BASIC Stamp 1, 2, and SX28AC/DP code examples (SX/B) are included at the end of this documentation. The RFID Reader Module is controlled with a single TTL-level active-low /ENABLE pin. When the /ENABLE pin is pulled LOW, the module will enter its active state and enable the antenna to interrogate for tags. The current consumption of the module will increase dramatically when the module is active.
PAGE 4
DC Characteristics At VCC = +5.0V and TA = 25ºC unless otherwise noted Parameter Supply Voltage Supply Current, Idle Supply Current, Active Input LOW voltage Input HIGH voltage Output LOW voltage Output HIGH voltage Symbol VCC IIDLE ICC VIL VIH VOL VOH Test Conditions ------+4.5V <= VCC <= +5.5V +4.5V <= VCC <= +5.5V VCC = +4.5V VCC = +4.5V Specification Min. Typ. Max. 4.5 5.0 5.5 --10 ----90 ------0.8 2.0 --------0.6 VCC - 0.
PAGE 5
Optional Tag Information Even though Parallax only carries a Round Tag and a Rectangle Tag the following values were obtained from different tags available in the market. ISO Card: World Tag 50mm: World Tag 30mm: Bobsleigh Keyfob: Tear shape: Wristband: 6.3cm 6.8cm 5.3cm 5.3cm 4.0cm 4.0cm (2.5") +/(2.7") +/(2.1") +/(2.1") +/(1.6") +/(1.6") +/- 10% 10% 10% 10% 10% 10% RFID Technology Overview Material in this section is based on information provided by the RFID Journal (www.rfidjournal.com).
PAGE 6
manufacturing cost), the Parallax RFID Reader Module's antenna was designed with a specific inductance and "Q" factor for 170kHz RFID operation at a tag read distance of up to 1 ¾” - 3” inches. Example Code The following code examples read tags from a RFID Reader Module and compare the values to known tags (stored in an EEPROM table). ' ========================================================================= ' ' File....... RFID.BS1 ' Purpose.... RFID Tag Reader / Simple Security System ' Author.....
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' -----[ EEPROM Data ]----------------------------------------------------Tags: EEPROM EEPROM EEPROM EEPROM EEPROM ("0F0184F20B") ("0F01D9D263") ("04129C1B43") ("0000000000") ("0000000000") ' valid tags ' space for other tags ' -----[ Initialization ]-------------------------------------------------Reset: HIGH Enable LOW Latch ' turn of RFID reader ' lock the door! ' -----[ Program Code ]---------------------------------------------------Main: LOW Enable ' SERIN RX, T2400, ($0A) ' SERIN RX, T2400, tag
PAGE 8
GOTO Main END ' ========================================================================= ' ' File....... RFID.BS2 ' Purpose.... RFID Tag Reader / Simple Security System ' Author..... (c) Parallax, Inc. -- All Rights Reserved ' E-mail..... support@parallax.com ' Started.... ' Updated.... 07 FEB 2005 ' ' {$STAMP BS2} ' {$PBASIC 2.
PAGE 9
SevenBit Inverted Open Baud CON CON CON CON #SELECT $STAMP #CASE BS2, BS2E TmAdj CON FrAdj CON #CASE BS2SX TmAdj CON FrAdj CON #CASE BS2P TmAdj CON FrAdj CON #CASE BS2PE TmAdj CON FrAdj CON #CASE BS2Px TmAdj CON FrAdj CON #ENDSELECT LastTag CON $2000 $4000 $8000 T2400 $100 $100 ' x 1.0 (time adjust) ' x 1.0 (freq adjust) $280 $066 ' x 2.5 ' x 0.4 $3C5 $044 ' x 3.77 ' x 0.265 $100 $0AA ' x 1.0 ' x 0.665 $607 $2A ' x 6.03 ' x 0.
PAGE 10
' -----[ Program Code ]---------------------------------------------------Main: LOW Enable #IF __No_SPRAM #THEN SERIN RX, T2400, [WAIT($0A), STR buf\10] #ELSE SERIN RX, T2400, [WAIT($0A), SPSTR 10] #ENDIF HIGH Enable Check_List: FOR tagNum = 1 TO LastTag FOR idx = 0 TO 9 READ (tagNum - 1 * 10 + idx), char #IF __No_SPRAM #THEN IF (char <> buf(idx)) THEN Bad_Char #ELSE GET idx, chkChar IF (char <> chkChar) THEN Bad_Char #ENDIF NEXT GOTO Tag_Found Bad_Char: NEXT ' activate the reader ' wait for hdr + ID ' de