Gadget Download

                             RFID is an acronym for Radio Frequency Identification. This project is a standalone Automatic two door interlock control system for toll tax using AT89S52 microcontroller. This project is useful in all applications where two door interlocking is needed. RFID is increasingly used with biometric technologies for security. Primarily, the two main components involved in a Radio Frequency Identification system are the Transponder (tags that are attached to the object) and the Interrogator (RFID reader). Communication between the RFID reader and tags occurs wirelessly and generally doesn’t require a line of sight between the devices.

                         

   RFID tags are categorized as either active or passive. This project uses passive tags. Read-only tags are typically passive and are programmed with a unique set of data (usually 32 to 128 bits) that cannot be modified. The reader has three main functions: energizing, demodulating and decoding. The antenna emits radio signals to activate the tag and to read and write data to it.

       In this project, the RFID module reader typically contains a module (transmitter and receiver), a control unit and a coupling element (antenna). This module is interfaced with the micro controller and when the card is brought near to the RFID module it reads the data in the card and displays on the LCD.

The aim of this project is to atomize the toll tax collection on highways. RFID reader, tags are used in this project to identify the entry or exit of the vehicle. The RFID reader is placed at the toll tax collecting area and each and every vehicle is provided with a RFID card. Each and every time when we place the RFID card on the reader the current value (in Rs) in the card has to be stored in the EEPROM. Once we pay the tax through RFID card the value of the card get decremented which can shown on 16X2 LCD.

Initially the gate is closed. Whenever any vehicle comes in front of the entry gate, the reader detects the RFID card owned by the vehicle owner and certain value of amount is detected automatically which will be displayed on 16X2 LCD. By using serial communication the data will be processed by the microcontroller and opens the entry gate by rotating the DC motor. After some delay, the gate will be closed.

The user places the RFID card in the RFID reader for collecting the tax, then. Then the exit gate opens for the vehicle to leave. The microcontroller closes the gate only after the vehicle exits out .If certain amount is not there in the card then he/she can renewal the RFID card. Once the amount is successfully deducted from RFID card only the gate opens. And again the RFID reader will be waiting for the next vehicle to enter.