EEL 4914 Senior Design

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EEL 4914 Senior Design

  1. 1. Project #6 EEL 4914 Senior Design Fall 2005 Final report Livestock RFID Tracking System for Developing Countries Accessible RFID Submitted by: Team 6 Eric Dattoli, ericd111@ufl.edu
  2. 2. Table of Contents Project Abstract ……………………1 Introduction ………………………..1 Technical Objectives ………………2 Concept Screening Matrix …………3 System Level Presentation ………...4 Final Product ………………………7 Study Organization ………………...8 References …………………………9 Project Abstract A low-frequency radio-frequency identification (RFID) reader system was developed. The system is capable of storing and displaying information associated with uniquely coded RFID tags. The system is targeted towards the livestock industry of developing countries. This reader system provides a way to track the health and status of livestock. The reader system consists of an antenna attached to a RFID transceiver. A LCD is used for display, and a keyboard for input. Data storage is provided by removable flash memory cards. The novel aspect of this project is that a low-cost RFID reader system has never been developed. Introduction In the past decade, the livestock industry of developed countries has begun implementing RFID tracking systems. The main purpose of these livestock tracking systems is for traceability in the event of a disease outbreak. The Mad Cow Disease outbreak in Britain has caused governments to take steps to curb the spread of a livestock disease in the event of a similar outbreak. Australia1 and Canada2 have already lawfully declared that all cattle in their countries must be tracked with RFID tags. The US is looking towards moving to this goal.3 Many non- OECD countries are also looking into RFID technology for similar reasons. Argentina and Taiwan have bought hundreds of thousands of tags from an American RFID company.4 Thailand, which is facing a possible avian flu outbreak, is also working with the company. Furthermore, RFID tracking improves the record keeping ability of the livestock industry. Detailed statistics about livestock are able to be compiled thanks to computer database systems. Statistics like growth rates, health, and yield are recorded. The efficiency of inventory tracking is also improved. The older method of inventory control consists of using paper and pen to record the serial numbers off of metal tags.5 RFID systems allow inventory tracking to be accomplished in an automated manner. As one can assume, RFID livestock tracking is much less widespread in least developed countries as compared to middle income countries like Argentina and Thailand. This project hopes to produce a RFID tracking system that least developed countries could afford. RFID tracking has the capability to greatly increase the efficiency of these countries’ livestock industry. Through the usage of RFID tracking, the country of Botswana has reduced the amount of cattle thefts by 60%. The Botswana government achieved this great success by implementing a mandatory RFID tracking program. In addition, the RFID tracking system enabled Botswana to meet the EU’s stringent requirement that all imported beef be traceable back to individual cattle. Botswana is now in position to be able to sell to the large EU beef market.6 The 2
  3. 3. Intermediate Technology Development Group charity is working to implement a similar program in Kenya. RFID livestock tracking solutions have been available for over a decade. Existing RFID tracking systems are expensive and are aimed for use by large corporations who can afford them. Texas Instruments has a RFID tracking solution called TIRIS which it markets to many companies, from clothing retailers and libraries to the livestock industry.7 It consists of a RFID reader system which connects to a PC. The reader system sends the data read from the RFID tags to the PC which is running proprietary software. The PC is used to display, interpret, and process the data. This system is very impracticable for least developed countries. The access to PCs in these countries is very limited, and the price tag of $670 for the RFID reader alone is too expensive. The objective for this project was to produce a RFID tracking system for less than $100. The Accessible RFID team designed and built a product which can read RFID tags and display information about the tags. Data transfer is provided by removable flash storage. The tracking system does not require the usage of a PC, and works with RFID tags which cost $1-2 each. Technical Objectives In Figure 1 is a top level system diagram of the RFID reader system. The system is capable of reading RFID tags within a 10 cm radius. The system is compatible with 125kHz Read-Only RFID tags. These tags each store a unique 40-bit number which is transmitted to the reader system. The system relies on a simple database to store the records associated with each unique RFID tag. The unique ID serves as the primary key and main identifier of a particular livestock animal. The system utilizes a PS/2 keyboard for input. Any industry standard keyboard is compatible. A 4-line, 20 character LCD screen is used to provide a practical display size at a low-cost and with low-power requirements. A real-time clock chip is used to keep track of local time. It is used to keep a record of when exactly the RFID tags are scanned. Once the user brings a RFID tag within close enough proximity, he may initiate a scan. If the scanned unique ID transmitted by the tag is not already present in the system’s database, a new record associated with the ID may automatically be added into the database. If the scanned tag is already present within the system’s database, the record associated with the tag is looked up in the database and displayed on the screen. The system will also save the exact time of this last scan of the tag in the database. Next, the system allows the user to either view or edit the information associated with the tag by using the keyboard. The user may view or edit text fields which hold information like health, location, or weight of the animal. Alternatively, the user may access this database by viewing and selecting from a list of unique tag IDs. The system also provides for removable data storage. MMC flash cards serve as a way to transfer data and to provide backups. The reader system’s entire tag database may be transferred to industry-standard removable MMC flash cards. In addition, previously saved databases on these cards may be copied back into the system. Furthermore, another system utility allows the user to manually edit the time on the real-time clock using the keyboard and a menu-based system. 3
  4. 4. Concept Screening Matrix Concept Screening Matrix, Accessible RFID Concepts A-F; compare with reference concept G. "+" implies better than reference, "0" equals reference, "-" less than reference. Reference Concept Concept Concept Concept Concept Concept A B C D E F Non- Melexis Melexis Melexis Melexis decoding transceiver, transceiver, transceiver, transceiver, transceiver, Customer/ Importance AC supply, AC supply, DC supply, DC supply, AC supply, TIRIS RF Market Needs Rating EEPROM MMC card EEPROM MMC card MMC card system Low Cost 5 + + 0 0 + 0 Low Power 5 0 0 - + 0 0 Good Documentation 4 + + + + + 0 Range 2 0 0 0 0 0 0 Functionality 3 + + + + - 0 Easy Programming 4 + + + + 0 0 Ease of Operation 3 0 + 0 + 0 0 Low Noise 3 0 0 0 0 0 0 Flexibility 2 - + - + 0 0 Durability 5 0 + - - 0 0 Sum +'s 16 "+" 26"+" 6 "+" 21 "+" 9 "+" Sum 0's 18 "0" 10 "0" 13 "0" 10 "0" 24 "0" Sum -'s 2 "-" 0 "-" 7 "-" 5 "-" 3 "-" Net Score(+=+1,0=0, -=-1) 14 26 -1 16 6 0 Rank III I V II IV Continue? no yes no no no no The original chosen system configuration was successfully built. No design changes were necessary, and the system as outlined in the project’s design document was built exactly as specified. The team’s main system design choice outlined that a more expensive RFID transceiver, made by Melexis, was to be used instead of a less expensive chip, like one produced by Atmel. The rationale for this decision is that the Melexis chip provides on-chip filtering and decoding, which simplifies the design of the entire product and lessens the amount of external filtering and software decoding needed. The price differential between the two chips is about $1 in large quantities, and the benefits gained by simplification of the design counterbalance the small additional cost. 4
  5. 5. System Level Presentation Specifications For Components in Figure 1 1.) RFID transponder (tags) Only compatible RFID transponders may be used with the reader system. World TAGs from Sokymat have been verified to work. Compatible transponder tags must match the transmission specs specified by the RFID transceiver module. 2.) RFID antenna The RFID antenna used is a simple coil of copper, approximately 10cm in radius. It was supplied by Melexis, part number MLX90125. The radius of the antenna is about the same length of a transponder; this fact allows for significant magnetic coupling between the antenna and the transponders. Data transmission is accomplished via magnetic coupling. The antenna has an inductance of 73.7 μH. In order to achieve a 125 kHz resonant frequency, a 22 nF capacitor was placed in parallel with the antenna. The resonant frequency of the antenna was validated using an oscilloscope and wave generator. The antenna was connected to the wave generator producing a 125 kHz sinusoid. The voltage amplitude on the antenna was measured to ensure that the max amplitude occurs very close to 125 kHz. 3.) RFID Transceiver Module The RFID transceiver used in the product is the Melexis MLX90109 chip. A transceiver module was built using this chip plus the antenna into a DIP-8 package. The system level representation of the module is in Figure 2. The module interfaces with the microprocessor using 2 wires, RFID_CLK and RFID_DATA. When transmission between a transponder and the module occurs: RFID_DATA synchronously transmits the digital 64-bit code serially to the attached microcontroller, while RFID_CLK serves as the serial clock. This module is compatible with RFID tags which transmit according to these specs: ASK modulation, Manchester or Biphase encoding, 2 or 4 kHz transmission rate, and 125 kHz transmission frequency. This module was tested using an oscilloscope to verify that a digital signal was transmitted on RFID_DATA when a transponder was brought into range. In Figure 3 is a schematic of the RFID transceiver module. The antenna system consists of a parallel LC circuit, where the antenna serves as the inductor. This antenna is connected to the MLX90109 RFID transceiver chip. The mode pins of the MLX90109 chip are set by the microprocessor by applying +5V or 0V to an on-board resistor network. The transmitted 64-bit code from the RFID tag contains a 40-bit unique ID. The 24 other bits are used for parity checking. See the code in the appendix for the procedure used for extracting and verifying the 40-bit unique ID. 5
  6. 6. Figure 2. Top-level RFID transceiver representation Figure 3. RFID Transceiver Module Schematic 4.) PIC microcontroller A PIC 18F452 microcontroller was used. This chip was programmed using the Crownhill Proton+ Basic Compiler (v. 2.1.3). The microcontroller was used for all system control and data processing functions. This was the only chip in the design that needed to be programmed. This chip is capable of triggering an external interrupt when a pin changes its logic level. This external interrupt capability was utilized to sample the synchronous serial transmission utilized by the PS/2 Keyboard and RFID transceiver module. The other feature utilized on the microcontroller was the hardware I2C interface. The EEPROM and RTC chips use the I2C interface to communicate with the microprocessor. 5.) MMC connector and MMC card The MMC connector used was the ALPS SCDA1A0701. The connector allows the insertion and removal of a MMC flash card. The MMC card uses SPI (4 wires) to communicate with the microcontroller. The MMC card must be run at 3.3V. A LM3904 power regulator was used to power the card. The 5V output by the PIC is stepped down to 3.3V using a resistor divider. The PIC interfaces with the MMC card, and can read and write to its flash memory, and thus verify the MMC card’s contents. Code was written for the microcontroller to interface with the MMC card according to Sandisk’s MMC specification. This code is included in the Appendix in the file mmc.int. 6
  7. 7. Figure 4. MMC Connector Interface 6.) 4-line Character LCD The LCD used displays 4 lines with 20 characters per line. The LCD uses a 4-bit data bus interface. The PIC microcontroller was used to interface with the LCD display. 7.) PS/2 Keyboard A DIN-6 connector is in order to connect to a PS/2 keyboard. The PIC microcontroller interfaces directly with the keyboard. Every time a key is pressed, the microcontroller is used to sample the transmitted 11-bit serial signal. Using software programming, the 11-bit code is converted into an ASCII character code. 8.) Real-Time Clock The real-time clock used was the DS1307. A watch battery is used so that time is kept when the reader system is powered off. This component interfaces with the microcontroller using the I2C bus. 9.) EEPROM A 256 kByte EEPROM was used to store the tag database. Figure 5. PS/2 Keyboard This component interfaces with the microcontroller using the Connector I2C bus. 7
  8. 8. Final Product A low-frequency radio-frequency identification (RFID) reader system was successfully produced. It met all of the product requirements that were initially planned. The system is able to scan RFID tags, and display their unique identifier code. This code is then used by the system to provide database storage of information associated with the RFID tag. The system provides database editing and viewing features useful for keeping track of livestock. The system utilizes a LCD for display, and a PS/2 keyboard for input. Users have the capability to backup or transfer their databases using MMC flash cards. A main design goal was to produce the system for less than $100. This goal was achieved. The total cost of the system is about $65, as outlined in Figure 6. This system costs much less than the $670 Texas Instrument’s TIRIS system and does not require the use of a PC. Although Accessible RFID’s reader system possesses far fewer features than the TIRIS system, it provides enough functionality for the smaller scale livestock concerns of developing countries, and at a price they can afford. Some of the limitations of the Accessible RFID system are that it is: short RFID antenna range of 10 cm, limited to 256 unique tags in memory, limited to 32 bytes of information stored for each tag in the database, and possesses no networking capability to work with other readers. Component Cost in large quantities LCD screen $20 Keyboard $5 MMC Flash Card $5 PIC microcontroller $5 RFID Transceiver $2 Antenna $3 AC/DC Power Supply $8 RFID transponders $1 each Real-Time Clock $3 EEPROM $3 PCB $10 Total Expected Cost $65 Figure 6. Expected cost of Accessible RFID Reader System 8
  9. 9. Study Organization Gantt Chart Weeks 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Introduction (team) Research/project proposal (team) Keyboard interface w/ PIC LED interface Nonvolatile memory Antenna construction/tuning detailed circuit detailed code breadboard test protel board 1 testing protel board 1 protel board 2 testing protel board 2 documentation demo Op1 The project was organized according to the above Gantt Chart. The project didn’t encounter any delays, and the original schedule stayed unchanged. The project was organized in three distinct phases. First, during the research phase, the entire reader system was planned out. The components that make up the system were chosen, and schematics were detailed for connecting them together. Second, during the breadboard stage, all of these components were wired together. Code was written for the microcontroller to control these components and process the data received from them. This prototype system was tested extensively and debugged. Third, the final design was fabricated onto a PCB. After testing, one revision of the PCB was produced and was validated to work properly. 9
  10. 10. References 10
  11. 11. 1 “Meat and Livestock Australia.” National Livestock Identification System http://www.mla.com.au/content.cfm?sid=1350 2 “Canada Expands RFID Policy To Stave Off Mad-Cow Disease.” RFIDinsights. July 21, 2005 http://www.rfidinsights.com/news/166401474 3 “USDA steps up efforts to track livestock.” CNN.com. May 28, 2004 http://www.cnn.com/2004/TECH/science/05/24/animalidentification/ 4 “Globalisation of RFID boosts Advanced ID sales.” Food Production Daily.com. 10/05/2004. <http://www.foodproductiondaily.com/news/news-ng.asp?id=51979-globalisation-of-rfid> 5 “RFID technology could be used to build a national livestock-tracking system.” InformationWeek. Jan. 12, 2004. http://www.informationweek.com/story/showArticle.jhtml? articleID=17300330&pgno=1 6 “Botswana using digital bolus to trace stolen cattle.” Intermediate Technology Development Group. March 29, 2005. <http://www.itdg.org/?id=peace5_cattle_tracking_botswana> 7 TI TIRIS RFID system. <www.ti.com/tiris> APPENDIX - Material and Resources • RFID transceiver (Melexis) • 8-bit PIC microcontroller • Antenna (coiled wire) • 4-line LCD • Keyboard • MMC flash card • RFID tags • AC power supply - Circuit Diagrams - Source Code

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