RFid Technology

TELE 480 Presentation

What is RFid?

• RFid is an ADC technology that uses radio-frequency waves to transfer data between a reader and movable item to identify, categorize, track…

• RFid is fast , reliable, and does not request physical sight or contact between reader/scanner and the tagged item

What is components of RFid system

• One or more RF tags

• Two or more antennas

• One or more interrogators (Reader)

• Middleware

• One or more host computers

• Appropriate software

What we have…

Continue…

Responds from tags

RFID Reader

Send commands

RFID Tag

Zaurus

CF Slot

Reader reading field

Communication

• Using the Java Communications API – Classes and interfaces are packaged in the javax.comm

package

– Interfaces: CommDriver,CommPortOwnershipListener, ParallelPortEventListener, and SerialPortEventListener.

– Classes: CommPort, CommPortIdentifier, ParallelPort, ParallelPortEvent, SerialPort, and SerialPortEvent.

– Exceptions: NoSuchPortException, PortInUseException, and InsupportedCommOperationException.

Communication java code

• Identify the serial port to which the reader is attached to the mobile device.

• Open and claim the ownership of the port.

• Resolve port ownership contention between multiple Java applications.

• Create an OutputStrean associated with the port.

Continue…

• Write the stream of data to the port. The stream of the data must conform to the PC-to-micro reader protocol. After the data is successfully written to the port, the reader switches into one of the modes as specified in the data field of the stream.

• Register an event listener to the port.• Specify an event type: notifyOnDataAvailable().• The event type calls the interface method

serialEvent()

Continue…

• Within the serialEvent method, the RFID tag data is read. When the tag is in the reader’s field, it transmits data to the reader, which in turn, transmits to the Zaurus via serial port

• The data is formatted and converted into the hexadecimal form.

• Open and take the ownership of the communication port to which the reader is connected.

Continue…

• Sending commands to switch the reader to one of its operation modes. A command is sent via the serial port to switch the reader to “comtinuous normal mode.” Now the reader continuously reads whenever a tag comes to its field.

• Register an event listener to the port, specify an event type, and handle the event. The tag data is read when an RFID tag comes in the field of the reader. This makes data available at the port. Availability of the data triggers the notifyOnDataAvailable() event, which is listened by the serialEvent() method where the data is fetched form the reader to the Zaurus.

Configure Zaurus

• Download ARM Java JRE from http://www.blackdown.org/. The version I used in this research is j2re-1.3.1-RC1-linux-arm.

• Transmitting the files we downloaded to SD card. In Zaurus, the SD card path is /mnt/card/ or /home/samba/SD_Card.

• Setting $JAVA_HOME: export JAVA_HOME=/home/samba/SD_Card/j2re-1.3.1-RC1-linux-arm/ j2re-1.3.1

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• Setting $CLASSPATH: export CLASSPATH=.:/home/samba/SD_Card/j2re-1.3.1-RC1-linux-arm/ j2re-1.3.1/lib/rt.jar: /home/samba/SD_Card/j2re-1.3.1-RC1-linux-arm/ j2re-1.3.1/lib/armv4l/libjava.so

• Setting $PATH: export PATH=$PATH:/ /home/samba/SD_Card/j2re-1.3.1-RC1-linux-arm/ j2re-1.3.1/bin/:/home/samba/SD_Card/j2re-1.3.1-RC1-linux-arm/ j2re-1.3.1/lib/armv4l/libjava.so

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• Adding LD_LIBRARY_PATH: LD_LIBRARY_PATH=$LD_LIBRARY_PATH: /home/samba/SD_Card/j2re-1.3.1-RC1-linux-arm/ j2re-1.3.1/lib/armv4l/

• Download java API from www.sun.com • We will get a folder names comm3.0_u1_linux.

We only need copy comm.jar and javax.comm.properties to the SD card.

• Now we export comm.jar: export CLASSPATH=$CLASSPATH:/home/samba/SD_Card/comm.jar

Continue…

• After exporting comm.jar, Java JRE can search the javax.comm.properties automatically when we place javax.comm.properties at the same directory as comm.jar

• Using “cd” command to go to /home/samba/SD_Card/j2re-1.3.1-RC1-linux-arm/ j2re-1.3.1/bin/ and use “./ java –version” command to test JRE.

• We compile the RFIDTagRead.java in Linux PC and copy RFIDTagRead .class to SD card.

• Now we only need to run the RFIDTagRead.class in Zaurus.

Serial port definition

The socket Reader Module accepts and sends data at RS232 levels using 1 start bit, 8 data bits, 1 stop bit, no parity and the baud rate is configurable to 9600, 19200, 38400 and 57600 baud. The data packet from the host to the reader is known as the request and reply from the reader to the host as the response. The host is always the primary station and initiates all communication sequences. These consist of request/response pairs where the host waits for a response before continuing.

Example Request Packet• 01 hex SOF• 0A hex LSbyte of length• 00 hex MSbyte of length• 00 hex LSbyte of node address• 00 hex MSbyte of node address• 00 hex Command flags (Not addressed)• 02 hex Command (Tag-itTM Read block)• 01 hex Data (Block number 1)• 08 hex LSbyte of Checksum• F7 hex MSbyte of Checksum

Command Definitions

0F hexSpecial Read Block Command05 hexRead Transponder Details

04 hexLock Single Non-addressed & Addressed Block

03 hexWrite Single Non-addressed & Addressed Block

02 hexRead Single Non-addressed & Addressed Block

Command CodeCommand Function (Tag-it HF)

Read Block Command (02 hex)• Reads a single block of data from a transponder. If the address flag is

set, the address forms the first part of the data section (LSbyte first), followed by a single byte containing the block number to be read. If the address flag is clear the data section only contains the block number.

Example• Read block 3 of a transponder whose address is 0134A4D5hex• Request packet• 01 0E 00 00 00 10 02 D5 A4 34 01 03 5A A5hex • The response packet is similar to the request packet, with the data

section containing the data received from the transponder (LSbyte first) followed by a single byte indicating the lock status and then another single byte containing the block address. The two LSB’s of the lock status byte reflect the two lock bits in the transponder.

Example• Response packet• 01 0F 00 00 00 00 02 33 22 11 00 00 03 0F F0 hex • 00112233hex read from unlocked block 3 of a transponder.

Thank you

Yang wang