RFID READER

RFID stands for Radio Frequency Identification. RFID is one member in the family of Automatic Identification and Data Capture ( AIDC ) technologies and is a fast and reliable means of identifying objects. There are two main components: The Interrogator (RFID Reader) which transmits and receives the signal and the Transponder (tag) that is attached to the object. An RFID tag is composed of a miniscule microchip and antenna. RFID tags can be passive or active and come in a wide variety of sizes, shapes, and forms. Communication between the RFID Reader and tags occurs wirelessly and generally does not require a line of sight between the devices. An RFID Reader can read through most anything with the exception of conductive materials like water and metal, but with modifications and positioning, even these can be overcome.

The RFID Reader emits a low-power radio wave field which is used to power up the tag so as to pass on any information that is contained on the chip. In addition, readers can be fitted with an additional interface that converts the radio waves returned from the tag into a form that can then be passed on to another system, like a computer or any programmable logic controller. Passive tags are generally smaller, lighter and less expensive than those that are active and can be applied to objects in harsh environments, are maintenance free and will last for years. These transponders are only activated when within the response range of an RFID Reader. Active tags differ in that they incorporate their own power source, where as the tag is a transmitter rather than a reflector of radio frequency signals which enables a broader range of functionality like programmable and read/write capabilities

RFID Applications

RFID is used for many applications such as:Automated electronic toll stations which can identify vehicles passing through without having to stop and then debits their account. Identify and monitor railcars and containers. RFID tags help farmers track their farm animals,and is used in wildlife conservation. Also helps to identify our animal companions if they should ever become lost. Customers can pay for their fuel at the pump with just a wave of their key tag. An increase in demand has been seen for security applications such as homeland security, employee identification, gaining entrance and controlling access of vehicles to buildings, gated communities, corporate campuses and airports. Some other current uses for RFID include waste management, automating parking and managingtraffic, the dispensing of all types of products, providing ski lift access, the tracking of library books and more. Major growth in the future of RFID will come from real-time location systems (RTLS), asset management, baggage handling and cash less payment systems. Business segments such as retail, logistics, warehousing and manufacturing will greatly benefit from an increase in supply chain visibility that RFID can create..

RFID Frequencies

Radio waves are the carriers of data between the reader and tags. The approach generally adopted for RFID communication is to allocate frequencies depending on application. The frequencies used cover a wide spectrum.

These specified bands are

Very long wave 9 - 135 kHzShort wave 13.56 MHzUHF 400-1200 MHzMicrowave 2.45 and 5.8 GHz

The allocation of frequencies is regulated by government agencies, requiring care in considering RFID applications in different countries. Efforts at standardization should

avert these problems. The many varied applications will work their best at different frequencies, therefore, it is important to understand the requirements before selecting a particular type of RFID system. The most common uses of low frequency systems are in security access, asset tracking and animal identification. They generally have short reading ranges and lower system costs. High-frequency systems are used for such applications as railroad car tracking and automated toll collection. They offer long reading ranges and high reading speeds. This higher performance usually entails higher costs. The power level of the interrogator and the power available within the tag to respond will determine the reading range that can be achieved in an RFID system. Like the restrictions on carrier frequencies there are legislative constraints on power levels. Environmental conditions, particularly at the higher frequencies, can also influence the range of communication

Hardware:

This RFID Reader is having 3 stages

RFID Reader Chip Pic Microcontroller to decode the data into Serial o/p and wigend O/p Rs232 to Convert signal into TTL to RS232

BLOCK DIAGRAM OF RFID READER NSK EDK 125KHZ

Data Transmission in ASCII Standard

Data read from the tag is Manchester encoded. The Manchester encoded data is decoded to ASCII standard. Decoded data is sent to the UART serial interface for wired communication with the host systems. ASCII data format is shown below:

For Example If The card Shown Above is Placed on the Reader , UART Data Will be 159 48659

Parity |---8BIT--|-------16BIT---------------|Parity

Wigend O/p Will be 1 1001 1111 1011 1110 0001 0011 0

Data Transmission in Wiegand26 Standard

The reader module supports the Wiegand standard that gives the Wiegand encoded output. This output comprises 3 bytes of data. It will be indicated as low pulse on data line if it is a Data 1 signal and low pulse on the zero line if it is a Data 0 signal.Figure 2 shows the pattern of data bits sent by the reader. This timing pattern falls within the Wiegand guidelines as prescribed by the SIA’s Access Control Standard Protocol for the 26-bit Wiegand Reader

Interface (a Pulse Width time between 20 μS and 100 μS, and a Pulse Interval time between 200 Μs and 20 mS).The Data 1 and Data 0 signals are held at logic high level (above the Voh level) until the reader is ready to send a data stream. The reader places the data as asynchronous low-going (negative) pulses (below the Vol level) on the Data 1 or Data 0 lines to transmit the data stream to the access control panel (the“saw-teeth” in Figure 2).The

Data 1 and Data 0 pulses do not overlap or occur simultaneously.The composition of the open existing industry standard 26- bit Wiegand format contains 8 bits for the facility code field and 16 bits for the ID number field. Mathematically these 8 facility code bits allow a total of 256 (0 to 255) facility codes, while the 16 ID number bits allow a total of only 65,536 (0 to 65,535) individual ID’s within each facility code.

SOFTWARE DETAILES

VISUAL BASIC 6.0

Visual Basic (VB) is the third-generation event-driven programming language and integrated development environment (IDE) from Microsoft for its COM programming model. VB is also considered a relatively easy to learn and use programming language, because of its graphical development features and BASIC heritage.

Visual Basic was derived from BASIC and enables the rapid application development (RAD) of graphical user interface (GUI) applications, access to databases using Data Access Objects, Remote Data Objects, or ActiveX Data Objects, and creation of ActiveX

controls and objects. Scripting languages such as VBA and VBScript are syntactically similar to Visual Basic, but perform differently.[2]

A programmer can put together an application using the components provided with Visual Basic itself. Programs written in Visual Basic can also use the Windows API, but doing so requires external function declarations.

VISUAL BASIC is a high level programming language which was evolved from the earlier DOS version called BASIC. BASIC means Beginners' All-purpose Symbolic Instruction Code. It is a very  easy programming language to learn. The codes look a lot  like English Language. Different software companies produced different version of BASIC, such as Microsoft QBASIC, QUICKBASIC, GWBASIC ,IBM BASICA and so on. However, it seems people only use Microsoft Visual Basic today, as it is a well developed programming language and supporting resources are available everywhere. Now, there are many versions of VB exist in the market, the most popular one and still widely used by many VB programmers is none other than Visual Basic 6. We also have VB.net, VB2005 and the latest VB2008, which is a fully object oriented programming (OOP) language. It is more powerful than VB6 but looks more complicated to master. If you wish to learn VB2008, click on the

VISUAL BASIC is a VISUAL and  events driven Programming Language. These are the main divergence from the old BASIC. In BASIC, programming is done in a text-only environment and the program is executed sequentially. In VB, programming is done in a graphical environment. In the old BASIC, you have to write program codes for each graphical object you wish to display it on screen, including its position and its color. However, In VB , you just need to drag and drop any graphical object anywhere on the form, and you can change its color any time using the properties windows.

On the other hand, because  users may click on a certain object randomly, so each object has to be programmed independently to be able to response to those actions (events). Therefore, a VB Program is made up of many subprograms, each has its own program codes, and each can be executed independently and at the same time each can be linked together in one way or another.

MS ACCESS DATABASE

Microsoft Office Access, previously known as Microsoft Access, is a relational database management system from Microsoft that combines the relational Microsoft Jet Database Engine with a graphical user interface and software development tools. It is a member of the Microsoft Office suite of applications, included in the Professional and higher editions or sold separately.

Access stores data in its own format based on the Access Jet Database Engine. It can also import or link directly to data stored in other Access databases, Excel, SharePoint lists, text, XML, Outlook, HTML, dBase, Paradox, Lotus 1-2-3, or any ODBC-compliant data container, including Microsoft SQL Server, Oracle, MySQL and PostgreSQL. Software developers and data architects can use it to develop application software, and "power users" can use it to build simple applications[citation needed]. Like other Office applications, Access is supported by Visual Basic for Applications, an object-oriented programming language that can reference a variety of objects including DAO (Data Access Objects), ActiveX Data Objects, and many other ActiveX components. Visual objects used in forms and reports expose their methods and properties in the VBA programming environment, and VBA code modules may declare and call Windows operating system functions.

MPLAB IDE

PIC is a family of Harvard architecture microcontrollers solely made by Microchip Technology.Microchip also makes the programming environment, MPLAB IDE in which all theprogramming, compiling and linking are done. C is a powerful programming language that enables the use of certain libraries to be used to help program functions for a specific need.All the code that is to be written will be done inside of MPLAB IDE. Also, the MPLAB will compile this code - turn C code into something the PIC can understand - and program it to the PIC. The figure below shows the basic look to a project in MPLAB. On the left showsall the files that are included in the project. The center window is the code file, where code would be written for compiling. On the right shows the output from the compiler, the linker,and eventual output from uploading the program to the PIC. Inside all of these windows iswhere the majority of the coding will occur.

PIC SIMULATOR IDE

Its a best simulator software for PIC microcontroller developed by oshonsoft to test your program, just browse and select the hex file which you have obtained after compiling the code, it also provides environment for testing your interfaces like LCD, stepper motor, LED board, and it also provides microcontroller view where you can provide inputs to the INPUT PORT pins and to check the output from the OUTPUT PORT pins.

PIC simulator IDE is powerful application that supplies PIC developers with user-friendly graphical development for windows with integrated simulator(emulator), basic compiler,

assembler, disassembler and debugger. PIC simulator IDE currently supports the following microcontrollers from the microchip PICmicro 12F and 16F product lines.

Main features of this simulator includes

main simulation interface showing internal microcontroller architecture. FLASH program memory editor, EEPROM data memory editor, hardware stack

viewer. microcontroller pinout interface for simulation of digital I/O and analog inputs. variable simulation rate, simulation statistics. breakpoint manager for code debugging with breakpoints support LCD module

simulation interface for character LCD modules. graphical LCD module simulation interface for 128x64 graphical LCD modules. stepper motor phase simulation interface for stepper motor driving visualization. 7-segment LED displays simulation interface