Radio Frequency Identification (RFID) technology at home and abroad in recent years has been developing rapidly. For the needs of battery-powered portable systems, power consumption is more and more attention. This article specifically addressed based on the MSP430F2012 and the CC1100 low-power design of two-way active tag hardware and software implementations. L
Q.How is the output power expressed in your Demo software? How is computed the radiate output power according to the antenna gain and cable loss?
A. Regarding the power settings, all of our demo applications require to insert the effective radiate power in mW ERP (Perp) that is related to the conducted RF power (Pw) provided at the reader's connector by the following formula:
where G is the antenna Gain expressed in dBi and L the cable attenuation expressed in dB.
The RF power to be set in the reader (Pw) in order to radiate the desired ERP power (Perp) is calculated by the software itself according to the above formula, then the calculated value is sent to the reader.
In particular for both CAEN RFID Show and CAEN RFID Java demo you shall insert the antenna gain expressed in dBi (for linear antennas) or dBic (for circular antennas) and the type of antenna you are using (circular or linear).
Please note that sometimes antenna manufacturers provides the gain of a circular antenna expressed in dBi. In this case you shall consider the antenna as a linear one and insert into the gain field this value (i.e. if antenna gain is 6dBi you shall enter gain=6 and type of antenna "linear"). As an alternative you can set the antenna as "circular" and increase by 3 the gain in dBi (i.e. if antenna gain is 6dBi you shall enter gain=9 and type of antenna "circular").
For CAEN Rfid Test program there is no antenna type setting so you shall operate as follows:
- If the antenna is linear you shall enter the gain expressed in dBi.
- If the antenna is circular and its gain is expressed in dBic you shall enter the gain decreased by 3.
- If the antenna is circular and its gain is expressed in dBi you shall enter the gain in dBi without any subctraction.
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Q.Which is the difference between the Linear polarized and the Circular polarized Antenna?
- A. Electric and magnetic fields radiated by linear polarized antenna are oriented along only one direction, on the contrary for circular polarized antenna EM fields rotate by tracing a circle perpendicular to the propagation direction.
A RFID tag is usually linear polarized, so with a linear polarized antenna the tag must be oriented in the same direction of the antenna. With a circular polarized antenna the tag can be oriented in any direction with respect to the antenna, even if only half of the radiated power density will be received by the tag. For this reason, with the same conducted input power, the ERP (Effective Radiated Power) of a circular polarized antenna is 3dB lower than the ERP of a linear polarized antenna that has the same gain (expressed in dBi).
- Q.Which is the reading range of your readers?
- A. There is not a standard reply to this question since the reading range strongly depends on a large number of factors such as the tag, the antenna with its cable, the tagged material and last but not least the testing environment. A typical value for our readers (medium and large sized) combined with the antennas, cables and A918 tags we provide with the kits is 5-6 m. This value can significantly drop down in an hostile environment or grow up in a favourable condition.
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There are numerous protocols using different approaches to each of these issues, and all of them work -- but the reader and tag need to use the same one! In this discussion we'll briefly examine the UHF tag protocol that has been promulgated by EPCglobal for supply-chain tracking using passive RFID tags. The EPCglobal protocols assume the tag carries a unique identifier, the electronic product code (EPC). EPC's can be either 64 or 96 bits long (longer ID's are available for future use), and are partitioned into a header describing the EPC structure, some information about the 'manager' (typically a company owning some ID space), and other information about the type of object marked and the serial number.
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Radio-frequency identification (RFID) is a technology that uses communication via electromagnetic waves to exchange data between a terminal and an electronic tag attached to an object, for the purpose of identification and tracking. Some tags can be read from several meters away and beyond the line of sight of the reader. The application of bulk reading enables an almost parallel reading of tags.
Radio-frequency identification involves interrogators (also known as readers), and tags (also known as labels).
Most RFID tags contain at least two parts. One is an integrated circuit for storing and processing information, modulating and demodulating a radio-frequency (RF) signal, and other specialized functions. The other is an antenna for receiving and transmitting the signal.
There are three types of RFID tags: passive RFID tags, which have no power source and require an external electromagnetic field to initiate a signal transmission, active RFID tags, which contain a battery and can transmit signals once an external source ('Interrogator') has been successfully identified, and battery assisted passive (BAP) RFID tags, which require an external source to wake up but have significant higher forward link capability providing greater range.
There are a variety of groups defining standards and regulating the use of RFID, including: International Organization for Standardization (ISO), International Electrotechnical Commission (IEC), ASTM International, DASH7 Alliance, EPCglobal. (Refer to Regulation and standardization below.)
RFID has many applications; for example, it is used in enterprise supply chain management to improve the efficiency of inventory tracking and management.
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Principally, the digital part of the UHF Demo Tag consists of: an ATMega128
microcontroller, a JTAG connector, a UART transceiver module, a serial-interface
connector, and a connector for an FPGA board (see Figure 10). Due to the high frequency
of the RF field that is emitted by the UHF reader, directly recovering the clock signal from
the RF field is no longer practical. Thus, the clock signal for the microcontroller is obtained
by an external crystal oscillator which generates a 16MHz clock signal.
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The power consumption of
the tag determines the operation distance of the tag from the reader
Important as well is the number of clock
cycles for executing the algorithm. Of minor relevance are the energy consumption and the maximum clock frequency.+
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Choosing the Reader
Generally, the same requirements as for the tag apply for the reader:
o Decryption of pseudonyms;
o Possibility of implementing Custom Commands;
o Storage of read keys for several tags;
o Portability.+
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RFID Sensor introduces its economy temperature sensor RFID system compatible with EPC Gen2 readers. The ST070-1 tag is specialized for sensing temperature for environmental sensing. The ST070-2 tag is specialized for sensing temperature of the particular surface on which it is mounted. Both tags provide superior range when mounted on metal or in open air. The ST070-series tags are fully passive tag with potential 30 years lifetime in the field sporting a hermeticity rating of IP-67.
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Identification (RadioFrequencyIdentification, RFID) nineties of the twentieth century the emergence of a non-contact automatic identification technology, which uses radio frequency signals to stationary or moving objects or persons of automatic identification. RFID data can be read and write with a signal penetration, and identify the range, and non-contact, multi-tag identification at the same time, information storage capacity, the advantages of strong confidentiality. In recent years, with progress in science and technology, RFID in manufacturing management, logistics and distribution management, medical management of a wide range of application areas. A general RFID system consists of hardware, software and basic data format and communication protocol components. Hardware includes RFID (Tag), reader (Reader) and the antenna is in three parts. Through the RFID reader and RFID tag antenna for wireless communications, the realization of the tag identification code and data memory read or write operation. Software, including middlewareapplication platform and application management software. Middleware can be shielded by different manufacturers, such as the RFID reader hardware systems, different hardware devices with different application software systems. RFID data format of the definition of an electronic tag data storage formats, communication protocols are mainly contained in the electronic tag and reader data transfer protocol.
Firstly, the tags and readers have a variety of communication protocols, the current standards have been identified there is ISO14443, ISO15693, ISO18000 and so on, which caused the current of the reader manufacturers have many models in the RFID system to RFID reader is very convenient to carry out configuration; Second, many of the company's RFID reader configuration software and business process monitoring software is the two sets of software, software for a low utilization rate.
RFID reader control functions to be completed: Serial operations (open, closed), reader initialization, label operations (detection of multiple, continuous detection of leaflets for multiple testing), reading data, writing labels data, write AFI, write DSFID, Lock AFI, lock DSFID.
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In this project we have to implement an embedded system design that integrates the monitoring of three biomedical parameters into a single personal medical device.
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Description: Radio Frequency Identification is a kind of object (Tag) that is used for identification purposes and is a type of contact less identification. This project is the hardware implementation of such system. This will use the microcontroller and RF Transceiver for the implementation. These techniques can be used for the attendance, automatic toll collection etc
Deliverables
- Selection of RFID components (i.e RF Chip, Microcontroller, antenna)
- Design the Reader for the RFID
- Design the Tag (Transponder) for the RFID
- Protocol for the communication between the Reader and Tag
Develop the protocol for removing the packet collision
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Project Title: Implementation and Designing of RFID(Radio Frequency Identification)Project Description:
Today, most companies use highly standardized barcode technologies, including UPCs, to identify and track products at an aggregate level through a supply chain. However, bar code technologies have serious limitations, e.g., line-of-site scanning.]. It is a technology that has been around for more than three decades, and it is still being used by retailers, manufacturers and logistics as a quick and easy way to track inventory.
RFID and EPC technologies offer a means to overcome the shortcomings of barcode technologies and provide additional benefits, including item-level (a pallet, a case, a product) identification, tracking, tracing.
Item tracking is a historical account of the item from its inception at a manufacturer's location, through various distribution centers, to customer takeoff at point of sale. By knowing where products are, in what quantities, and when and how they're moving, companies achieve enhanced visibility over their operations and supply chains. Greater visibility helps companies 1) reduce stock outs and corresponding lost sales, 2) foster the development of more efficient replenishment processes, and 3) reduce inventory to free precious cash.
The RFID initiative is based on the following key principles:
· Foster the adoption of open-source technology and open standards in the industry and public administration.
· Contribute to the growth of an ecosystem that may bring business opportunities to industry stakeholders.
· Structure the initiative as a re-usable process with publication of the underlying principles and processes.
· Promote alternative ways of thinking with a publication of real-world use-cases and corresponding IT solutions.
· Share technical expertise, identify technology commons and define best practices that leverage the reuse of open-source components.
The discussions within the RFID initiative gives rise to the publishing of their results under the copy left method, every participants being the co-author of those publications. The leader of the initiative proposes thinking and action plans.
Deliverable:
The final deliverable will be a hardware containing RFID reader and a transponder. The communication between a reader and a transponder will be full duplex through RF link. We will design a specific RF protocol for the communication. A database may also be maintained having EPC’s of different tags, so that it can be used to search for specific object.The Processing Code
Now that you’ve got a picture of the basic functionality, here’s the code. It’s divided into three tabs in the Processing sketch. The main tab provides functionality to communicate with the Arduino module. The buttons tab provides methods for making and drawing user buttons on the screen. It’s basically the same as the buttons tab in the RFID writer tutorial. The profiler tab provides the functions necessary to make the HTTP request to the PHP scrips below, and to parse the XML record that comes back from the request.
You’ll need to import the serial library to access the serial port. In addition, there are a few global variables at the top of the main tab to do some housekeeping, like manage the text in teh screen, keep track of the tags you’ve read from the reader, and save your own tag to a file on your computer so the sketch knows who you are.
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The setup() method initializes the serial port and the font for drawing text on the screen, makes the user interface buttons, and checks to see if there’s a file with your RFID tag saved in the sketch folder.
The draw() method is very simple. It calls two routines to draw the user interface buttons and the user profile if one has been retrieved from the web, and draws the text on the screen to let you know what’s been communicated to and from the reader.
The serialEvent() method is called automatically every time there is new serial data available. The serial library buffers the serial data until a newline character (n) is received, then it generates the serialEvent(). The method itself calls another method called parseForTag() to look for an RFID tag string in the incoming data. If it finds one, it checks to see if you requested that this be saved as your own tag. If so, it saves the tag to a file in the sketch folder. If not, it adds it to a string of received tags:
The aforementioned parseForTag() method scans each line of text received and looks for a colon. It assumes anything after the colon is an RFID tag string. When it finds a tag, it returns it:
A method called buttonPressed() is called when the user releases the mouse button over one of the user interface buttons. It determines which button was pressed and takes the appropriate action:
The makeRequest() method adds the RFID tag string to the end of the URL string, makes the HTTP call, and waits for the results. Then it saves the results in a file. Finally, it parses the results for a valid XML record using the parseRecord() method:
The parseRecord() method does just that: it opens the file created by the previous method and parses it for the XML data. Processing’s XMLElement object always reads from a file, so that’s why the two methods use a file to exchange the record. Before parsing the XML, this method checks to see that the file begins with an XML header. If it doesn’t, the method stops, clears the record variables and returns. It does this because the O’Reilly API sometimes returns HTTP error messages instead of XML, for example, if you give it a tag that’s not in the database.