28340 Datasheet 28340, 28140 | P1-P3

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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



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

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

PC, Macintosh, or Linux machines

 Bi-color LED for visual indication of status

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 2

, 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 from the 28340 product page at www.parallax.com.

The Debug Terminal within the Parallax BASIC Stamp Editor (www.parallax.com/basicstampsoftware)

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.

P1-P3 P4-P6 P7-P9 P10-P11

28340

Mfr. #:

Buy 28340

Manufacturer:

Parallax

Description:

RFID Transponders RFID Reader USB

Lifecycle:

New from this manufacturer.

Delivery:

DHL FedEx Ups TNT EMS

Payment:

T/T Paypal Visa MoneyGram Western Union

28340

28340

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