2814028340 Datasheet

Datasheet Feedback/Errors

ce 7&3 WALL/Ix z :2; 0) <7 2="" 45v="" (52="" 2mm)="" 4.="" p7="" ”wm="" 44="" p="" w]="" 44="" ©="" ©="" ©="" ©="" 2="" 45="" (52="" 2mm)="" ‘7="" 325w“="" 5mm)="" 4.="" 2="" 95-="" [75mm}="" l="" 1*="" #7="" l="" 1*="" o="" w="" (a="" 5mm}="" 01"(3="" 5mm}="" 4="" p="">

Web Site: www.parallax.com

Forums: forums.parallax.com

Sales: sales@parallax.com

Technical: support@parallax.com

Office: (916) 624-8333

Fax: (916) 624-8003

Sales: (888) 512-1024

Tech Support: (888) 997-8267

RFID Card Reader, Serial (#28140)

RFID Card Reader, USB (#28340)

Introduction

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

Frequency Identification (RFID) Card Readers provide a low-cost solution to read passive RFID

transponder tags up to 4 inches away. The RFID Card Readers can be used in a wide variety of hobbyist

and commercial applications, including access control, user identification, robotics navigation, inventory

tracking, payment systems, car immobilization, and manufacturing automation. The RFID Card Reader is

available in two versions: A TTL-level serial interface for use with a microcontroller and a USB interface

for direct connection to a computer.

Features

y Low-cost method for reading passive, 125 kHz RFID transponder tags

y Two easy-to-use versions: Serial interface for microcontrollers and USB for direct connection to

PC, Macintosh, or Linux machines

y Bi-color LED for visual indication of status

©mAxiw

RFID Compatibility

The Parallax RFID Card Reader works exclusively with the EM Microelectronics EM4100-family of passive

read-only transponder tags. Each transponder tag contains a unique, read-only identifier (one of 240, or

1,099,511,627,776 possible combinations).

A variety of different tag types and styles exist with the most popular made available from Parallax.

Connections (Serial)

The Parallax RFID Card Reader Serial version easily interfaces to any host microcontroller using only four

connections (VCC, /ENABLE, SOUT, GND).

Pin Pin Name Type Function

1 VCC P System power. +5V DC input.

2 /ENABLE I Module enable pin. Active LOW digital input. Bring this pin LOW to

enable the RFID reader and activate the antenna.

3 SOUT O

Serial output to host. TTL-level interface, 2400 bps, 8 data bits, no parity,

1 stop bit.

4 GND G System ground. Connect to power supply’s ground (GND) terminal.

Note: Type: I = Input, O = Output, P = Power, G = Ground

Use the following example circuit for connecting the Parallax RFID Card Reader:

Connections (USB)

The Parallax RFID Card Reader USB version can be connected directly to any PC, Macintosh, or Linux

machine that has a USB port and the appropriate drivers installed. The module is powered from the host

computer’s USB port and uses an industry-standard FTDI FT232R device to provide the USB connectivity.

FTDI drivers are available from www.ftdichip.com/Drivers/VCP.htm.

Signal Port Name Function

RX Serial Receive Serial output to host. 2400 bps, 8 data bits, no parity, 1 stop bit.

DTR Data Terminal Ready

Module enable. Bring the DTR line HIGH to enable the RFID

reader and activate the antenna. Bring the DTR line LOW to

disable the RFID reader.

When the Parallax RFID Card Reader is connected to the host computer, it will appear as a Virtual COM

port and will have a COM port number automatically assigned to it. This COM port can be accessed by

any software application, programming language, or interface that provides COM port connectivity and

will allow you to read the data stream transmitted by the module.

An example program, including Visual Basic/VB.net source code, for reading tags in Windows XP/Vista is

available on the Parallax website at http://forums.parallax.com/forums/default.aspx?f=21&m=269675.

The DEBUG window within the Parallax BASIC Stamp Editor (www.parallax.com/tabid/441/Default.aspx)

provides functionality to set the state of a COM port’s DTR line. Checking the DTR box in the toolbar will

activate the RFID Card Reader.

Usage

A visual indication of the state of the RFID Card Reader is given with the on-board LED. When the

module is successfully powered-up and is in an idle state, the LED will be GREEN. When the module is in

an active state searching for or communicating with a valid tag, the LED will be RED.

The RFID Card Reader Serial version is activated via the /ENABLE pin on the module’s 4-pin header.

When the RFID Card Reader is powered and /ENABLE is pulled LOW, the module will enter the active

state. When /ENABLE is pulled HIGH or left unconnected, the module will enter the idle state.

The RFID Card Reader USB version is activated via the DTR line of the USB Virtual COM port. When the

DTR line is set HIGH, the module will enter the active state. When the DTR line is set LOW, the module

will enter the idle state.

The face of the RFID tag should be held parallel to the front or back face of the antenna (where the

majority of RF energy is emitted). If the tag is held sideways (for example, perpendicular to the

antenna), you’ll either get no reading or a poor reading distance. Only one transponder tag should be

held up to the antenna at any time. The use of multiple tags at one time will cause tag collisions and the

reader may not detect any of them. The tags available in the Parallax store have a read distance of

approximately 4 inches. Actual distance may vary slightly depending on the size of the transponder tag

and environmental conditions of the application.

Communication Protocol

All communication is 8 data bits, no parity, 1 stop bit, and least significant bit first (8N1) at 2400 bps.

The RFID Card Reader Serial version transmits data as 5V TTL-level, non-inverted asynchronous serial.

The RFID Card Reader USB version transmits the data through the USB Virtual COM Port driver. This

allows easy access to the serial data stream from any software application, programming language, or

interface that can communicate with a COM port.

When the RFID Card Reader is active and a valid RFID transponder tag is placed within range of the

activated reader, the tag’s unique ID will be transmitted as a 12-byte printable ASCII string serially to the

host in the following format:

Unique ID

Digit 1

Start Byte

(0x0A) Unique ID

Digit 2 Unique ID

Digit 3 Unique ID

Digit 4 Unique ID

Digit 5 Unique ID

Digit 6 Unique ID

Digit 7 Unique ID

Digit 8 Unique ID

Digit 9 Unique ID

Digit 10 Stop Byte

(0x0D)

The start byte and stop byte are used to easily identify that a correct string has been received from the

reader (they correspond to line feed and carriage return characters, respectively). The middle ten bytes

are the actual tag's unique ID. For example, for a tag with a valid ID of 0F0184F07A, the following bytes

would be sent: 0x0A, 0x30, 0x46, 0x30, 0x31, 0x38, 0x34, 0x46, 0x30, 0x37, 0x41, 0x0D.

Interference

The Parallax RFID Card Reader, like many RF devices, may experience RF noise in its frequency range.

This may cause the reader to transmit a spurious tag response when no tag is near the unit. This will not

affect most uses of the RFID Card Reader. To avoid treating spurious responses as legitimate tags, it is

recommended to read two responses in a row within a given amount of time (for example, one second)

to ensure that you are reading a valid tag and not a “tag” generated by noise.

DC Characteristics

At VCC = +5.0V and TA = 25ºC unless otherwise noted

Test Specification

Parameter Symbol Conditions Min. Typ. Max. Unit

Supply Voltage VCC --- 4.5 5.0 5.5 V

Supply Current, Idle IIDLE --- --- 10 --- mA

Supply Current, Active ICC --- --- 100 200 mA

Input LOW voltage VIL +4.5V <= VCC <= +5.5V --- --- 0.8 V

Input HIGH voltage VIH +4.5V <= VCC <= +5.5V 2.0 --- --- V

Output LOW voltage VOL V

CC = +4.5V --- --- 0.6 V

Output HIGH voltage VOH V

CC = +4.5V VCC - 0.7 --- --- V

Absolute Maximum Ratings

Condition Value

Operating Temperature -40ºC to +85ºC

Storage Temperature -55ºC to +125ºC

Supply Voltage (Vcc) +4.5V to +5.5V

Ground Voltage (Vss) 0V

Voltage on any pin with respect to Vss -0.3V to +7.0V

NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage

to the device. This is a stress rating only and functional operation of the device at those or any other

conditions above those indicated in the operation listings of this specification is not implied. Exposure to

maximum rating conditions for extended periods may affect device reliability.

RFID Technology Overview

Material in this section is based on information provided by the RFID Journal (www.rfidjournal.com).

Radio Frequency Identification (RFID) is a generic term for non-contacting technologies that use radio

waves to automatically identify people or objects. There are several methods of identification, but the

most common is to store a unique serial number that identifies a person or object on a microchip that is

attached to an antenna. The combined antenna and microchip are called an "RFID transponder" or "RFID

tag" and work in combination with an "RFID reader" (sometimes called an "RFID interrogator").

An RFID system consists of a reader and one or more tags. The reader's antenna is used to transmit

radio frequency (RF) energy. Depending on the tag type, the energy is "harvested" by the tag's antenna

and used to power up the internal circuitry of the tag. The tag will then modulate the electromagnetic

waves generated by the reader in order to transmit its data back to the reader. The reader receives the

modulated waves and converts them into digital data.

There are two major types of tag technologies. "Passive tags" are tags that do not contain their own

power source or transmitter. When radio waves from the reader reach the chip’s antenna, the energy is

converted by the antenna into electricity that can power up the microchip in the tag (typically via

inductive coupling). The tag is then able to send back any information stored on the tag by modulating

the reader’s electromagnetic waves. "Active tags" have their own power source and transmitter. The

power source, usually a battery, is used to run the microchip's circuitry and to broadcast a signal to a

reader. Due to the fact that passive tags do not have their own transmitter and must reflect their signal

to the reader, the reading distance is much shorter than with active tags. However, active tags are

typically larger, more expensive, and require occasional service.

Frequency refers to the size of the radio waves used to communicate between the RFID system

components. Just as you tune your radio to different frequencies in order to hear different radio stations,

RFID tags and readers must be tuned to the same frequency in order to communicate effectively. RFID

systems typically use one of the following frequency ranges: low frequency (or LF, around 125 kHz), high

frequency (or HF, around 13.56 MHz), ultra-high frequency (or UHF, around 868 and 928 MHz), or

microwave (around 2.45 and 5.8 GHz).

The read range of a tag ultimately depends on many factors: the frequency of RFID system operation,

the power of the reader, and interference from other RF devices. Balancing a number of engineering

trade-offs (antenna size v. reading distance v. power v. manufacturing cost), the Parallax RFID Card

Reader's antenna was designed specifically for use with low-frequency (125 kHz) passive tags with a read

distance of around 4 inches.

BASIC Stamp® 1 Program

The following code examples read tags from a RFID Card Reader and compare the values to known tags

(stored in an EEPROM table).

' =========================================================================

' File....... RFID.BS1

' Purpose.... RFID Tag Reader / Simple Security System

' E-mail..... support@parallax.com

' Started....

' Updated.... 07 FEB 2005

' {$STAMP BS1}

' {$PBASIC 1.0}

' =========================================================================

' -----[ Program Description ]---------------------------------------------

' Reads tags from a Parallax RFID reader and compares to known tags (stored

' in EEPROM table). If tag is found, the program will disable a lock.

' -----[ Revision History ]------------------------------------------------

' -----[ I/O Definitions ]-------------------------------------------------

SYMBOL Enable = 0 ' low = reader on

SYMBOL RX = 1 ' serial from reader

SYMBOL Spkr = 2 ' speaker output

SYMBOL Latch = 3 ' lock/latch control

' -----[ Constants ]-------------------------------------------------------

SYMBOL LastTag = 2 ' 3 tags; 0 to 2

' -----[ Variables ]-------------------------------------------------------

SYMBOL tag0 = B0 ' RFID bytes buffer

SYMBOL tag1 = B1

SYMBOL tag2 = B2

SYMBOL tag3 = B3

SYMBOL tag4 = B4

SYMBOL tag5 = B5

SYMBOL tag6 = B6

SYMBOL tag7 = B7

SYMBOL tag8 = B8

SYMBOL tag9 = B9

SYMBOL tagNum = B10 ' from EEPROM table

SYMBOL pntr = B11 ' pointer to char in table

SYMBOL char = B12 ' character from table

' -----[ EEPROM Data ]-----------------------------------------------------

Tags:

EEPROM ("0F0184F20B") ' valid tags

EEPROM ("0F01D9D263")

EEPROM ("04129C1B43")

EEPROM ("0000000000") ' space for other tags

EEPROM ("0000000000")

' -----[ Initialization ]--------------------------------------------------

Reset:

HIGH Enable ' turn of RFID reader

LOW Latch ' lock the door!

' -----[ Program Code ]----------------------------------------------------

Main:

LOW Enable ' activate the reader

SERIN RX, T2400, ($0A) ' wait for header

SERIN RX, T2400, tag0, tag1, tag2, tag3, tag4 ' get tag bytes

SERIN RX, T2400, tag5, tag6, tag7, tag8, tag9

HIGH Enable ' deactivate reader

Check_List:

FOR tagNum = 0 TO LastTag ' scan through known tags

pntr = tagNum * 10 + 0 : READ pntr, char ' read char from DB

IF char <> tag0 THEN Bad_Char ' compare with tag data

pntr = tagNum * 10 + 1 : READ pntr, char

IF char <> tag1 THEN Bad_Char

pntr = tagNum * 10 + 2 : READ pntr, char

IF char <> tag2 THEN Bad_Char

pntr = tagNum * 10 + 3 : READ pntr, char

IF char <> tag3 THEN Bad_Char

pntr = tagNum * 10 + 4 : READ pntr, char

IF char <> tag4 THEN Bad_Char

pntr = tagNum * 10 + 5 : READ pntr, char

IF char <> tag5 THEN Bad_Char

pntr = tagNum * 10 + 6 : READ pntr, char

IF char <> tag6 THEN Bad_Char

pntr = tagNum * 10 + 7 : READ pntr, char

IF char <> tag7 THEN Bad_Char

pntr = tagNum * 10 + 8 : READ pntr, char

IF char <> tag8 THEN Bad_Char

pntr = tagNum * 10 + 9 : READ pntr, char

IF char <> tag9 THEN Bad_Char

GOTO Tag_Found ' all match -- good tag

Bad_Char:

Bad_Tag:

SOUND Spkr, (25, 80) ' groan

PAUSE 1000

GOTO Main

Tag_Found:

DEBUG #tagNum, CR ' for testing

HIGH Latch ' remove latch

SOUND Spkr, (114, 165) ' beep

LOW Latch ' restore latch

GOTO Main

END

BASIC Stamp® 2 Program

The following code examples read tags from a RFID Card Reader and compare the values to known tags

(stored in an EEPROM table).

' =========================================================================

' File....... RFID.BS2

' Purpose.... RFID Tag Reader / Simple Security System

' E-mail..... support@parallax.com

' Started....

' Updated.... 07 FEB 2005

' {$STAMP BS2}

' {$PBASIC 2.5}

' =========================================================================

' -----[ Program Description ]---------------------------------------------

' Reads tags from a Parallax RFID reader and compares to known tags (stored

' in EEPROM table). If tag is found, the program will disable a lock.

' -----[ Revision History ]------------------------------------------------

' -----[ I/O Definitions ]-------------------------------------------------

Enable PIN 0 ' low = reader on

RX PIN 1 ' serial from reader

Spkr PIN 2 ' speaker output

Latch PIN 3 ' lock/latch control

' -----[ Constants ]-------------------------------------------------------

#SELECT $STAMP

#CASE BS2, BS2E, BS2PE

T1200 CON 813

T2400 CON 396

T4800 CON 188

T9600 CON 84

T19K2 CON 32

TMidi CON 12

T38K4 CON 6

#CASE BS2SX, BS2P

T1200 CON 2063

T2400 CON 1021

T4800 CON 500

T9600 CON 240

T19K2 CON 110

TMidi CON 60

T38K4 CON 45

#CASE BS2PX

T1200 CON 3313

T2400 CON 1646

T4800 CON 813

T9600 CON 396

T19K2 CON 188

TMidi CON 108

T38K4 CON 84

#ENDSELECT

SevenBit CON $2000

Inverted CON $4000

Open CON $8000

Baud CON T2400

#SELECT $STAMP

#CASE BS2, BS2E

TmAdj CON $100 ' x 1.0 (time adjust)

FrAdj CON $100 ' x 1.0 (freq adjust)

#CASE BS2SX

TmAdj CON $280 ' x 2.5

FrAdj CON $066 ' x 0.4

#CASE BS2P

TmAdj CON $3C5 ' x 3.77

FrAdj CON $044 ' x 0.265

#CASE BS2PE

TmAdj CON $100 ' x 1.0

FrAdj CON $0AA ' x 0.665

#CASE BS2Px

TmAdj CON $607 ' x 6.03

FrAdj CON $2A ' x 0.166

#ENDSELECT

LastTag CON 3

#DEFINE __No_SPRAM = ($STAMP < BS2P) ' does module have SPRAM?

' -----[ Variables ]-------------------------------------------------------

#IF __No_SPRAM #THEN

buf VAR Byte(10) ' RFID bytes buffer

#ELSE

chkChar VAR Byte ' character to test

#ENDIF

tagNum VAR Nib ' from EEPROM table

idx VAR Byte ' tag byte index

char VAR Byte ' character from table

' -----[ EEPROM Data ]-----------------------------------------------------

Tag1 DATA "0F0184F20B" ' valid tags

Tag2 DATA "0F01D9D263"

Tag3 DATA "04129C1B43"

Name0 DATA "Unauthorized", CR, 0

Name1 DATA "George Johnston", CR, 0

Name2 DATA "Dick Miller", CR, 0

Name3 DATA "Mary Evans", CR, 0

' -----[ Initialization ]--------------------------------------------------

Reset:

HIGH Enable ' turn of RFID reader

LOW Latch ' lock the door!

' -----[ Program Code ]----------------------------------------------------

Main:

LOW Enable ' activate the reader

#IF __No_SPRAM #THEN

SERIN RX, T2400, [WAIT($0A), STR buf\10] ' wait for hdr + ID

#ELSE

SERIN RX, T2400, [WAIT($0A), SPSTR 10]

#ENDIF

HIGH Enable ' deactivate reader

Check_List:

FOR tagNum = 1 TO LastTag ' scan through known tags

FOR idx = 0 TO 9 ' scan bytes in tag

READ (tagNum - 1 * 10 + idx), char ' get tag data from table

#IF __No_SPRAM #THEN

IF (char <> buf(idx)) THEN Bad_Char ' compare tag to table

#ELSE

GET idx, chkChar ' read char from SPRAM

IF (char <> chkChar) THEN Bad_Char ' compare to table

#ENDIF

GOTO Tag_Found ' all bytes match!

Bad_Char: ' try next tag

Bad_Tag:

tagNum = 0

GOSUB Show_Name ' print message

FREQOUT Spkr, 1000 */ TmAdj, 115 */ FrAdj ' groan

PAUSE 1000

GOTO Main

Tag_Found:

GOSUB Show_Name ' print name

HIGH Latch ' remove latch

FREQOUT Spkr, 2000 */ TmAdj, 880 */ FrAdj ' beep

LOW Latch ' restore latch

GOTO Main

END

' -----[ Subroutines ]-----------------------------------------------------

' Prints name associated with RFID tag

Show_Name:

DEBUG DEC tagNum, ": "

LOOKUP tagNum,

[Name0, Name1, Name2, Name3], idx ' point to first character

READ idx, char ' read character from name

IF (char = 0) THEN EXIT ' if 0, we're done

DEBUG char ' otherwise print it

idx = idx + 1 ' point to next character

LOOP

RETURN

2814028340 Datasheet

INFORMATION

HELP

CONTACT US

FOLLOW US