Paper - RFID Access Control System using 8051 Micro Controller
Descrição do Produto
RFID Based Access Control System using 8051 Micro Controller
ABSTRACT
Objective of the Project The main objective of this project is to provide security to organizations like Schools, Hospitals, Office spaces, Industrial areas etc by limiting the access to a secured area only to the authorized personnel with a valid RFID Tag. A security lock is created using an RFID Reader module and RFID Tags. Access will be granted to people who hold an authorized RFID Tag only. Security is very important to each and every organization. Restricting access to very important and administrative areas are a priority nowadays in many organizations. Such areas are called “ secured areas” where access is limited to a certain set of people who are authorized. Proposed Working Model An RFID based Door Lock or Access Control System is based on some simple concepts. We store a set of RFID tag data (unique RFID codes/keys) inside our program/system, say 3 or 10 RFID tag data (the number varies according to requirements of user, say 10 tags needed if access needs to be granted to 10 people). The system comprises of a micro controller (8051 series), an RFID Reader module, an LCD module (16x2) to display messages, a 12 volts relay (to control output), and a power supply circuitry to give power to microcontroller, RFID module, LCD module and the relay. When the person with the right RFID tag (compatible to the data preloaded in our program/system) come and swipes his RFID tag near the RFID reader, access will be granted (a success message will be displayed on the LCD module and the relay will be turned ON). When the person with the wrong RFID card (whose data is not loaded in our system) swipes his RFID tag, access will be denied (a denial message will be displayed on the LCD module and the relay will not be turned ON). The 16x2 LCD module will display different status messages. Hardware Requirements Component
Specification
Microcontroller
8051 Series (AT89S51)
RFID Reader
EM18 Reader module (125Khz)
RFID Tags
Card Type (125Khz)
LCD Module
16x2 LCD JHD162A
Relay
12 volts, SPDT
Voltage Regulator
7805 (5 volts IC), 7812 (12 volts IC)
Rectifier
W10 Bridge
Transistor
2N2222 (for driving relay)
Transformer
12012
Others
Crystal,Capacitors, Resistors, Switches, Diodes,Connectors, Power cable
System Software Software development involves 4 stages: Stage 1 → Saving the authorized RFID keys Stage 2 → Reading an RFID Tag for comparison Stage 3 → Comparing the read RFID key with the saved values Stage 4 → Output grant or deny access based on comparison stage output Languages: Assembly (MCS51 instruction set) or Embedded C| Compiler: Keil or MIDE51 How RFID System Works RFID Tags have an integrated chip embedded inside it which will energise itself in an electromagnetic field. The chip inside this RFID tag stores a unique information which we call as the RFID key which is usually a 12 digit code including numbers and alphabets. This code is unique to each and every RFID tag. This code inside the chip can be read by an RFID Reader. A typical RFID tag will be in the shape of a smart card (as shown below). However, there are RFID tags in other shapes as well. An RFID tag comes with a chip with memory to store RFID identification code, a coil and a modulator. The coil is to energise the chip when the tag is placed near an RFID reader (which also has a coil inside) via electromagnetic induction. The modulator modulates the RFID code/key according to the frequency and transmits the information electromagnetically so that the RFID Reader can receive the information. The coil also serves as an antenna to send the modulated information to air medium. Note: RFID Tags are available in Passive and Active formats. The information written above is about passive RFID tag which is the most commonly used RFID tag. An active RFID tag has a battery inside it and sends the unique RFID information at set time intervals. This project makes use of a passive RFID tag.
RFID Reader usually comes in market as a module with a demodulator, coil and associated electronics. RFID reader is an active device and should be powered . The coil serves as exciter for the RFID tag (to energise the coil inside the tag) and also as an antenna for receiving the signal propagated by the RFID tag. The electronic circuit demodulates this signal and converts it into a form suitable for the next stage (to be sent to the microcontroller). Block Diagram
Expected Outputs! In real life, RFID based access control systems are associated with doors and solenoid locks (an electronically controlled lock).When an authorized person access the RFID system with his authorized RFID tag, the solenoid lock will open. Once the lock is open, the person can enter through the door. If an unauthorized person attempts to get access, the system will not open the solenoid lock (in fact, the lock will continue on its closed position). The solenoid lock is interfaced to the RFID system through a SPDT relay. To demonstrate actual working of the project, a lamp bulb is used instead of the door (and the solenoid lock). The lamp bulb is interfaced to the RFID system using an SPDT relay. An LCD module (16x2) is used to display status messages. The LCD module has 2 lines. The first line is used to display random messages. At the time of system boot, a message “RFID based access control” will be displayed for a few seconds. Once the system is ready, a permanent message “Swipe RFID Tags” will be displayed on the first line of LCD module. The second line of LCD module is used display different output status messages on event of someone showing/swiping their RFID cards. There are two possible outputs! One for Successful Access and one for Failed Access! 1) Successful Access If the RFID Tag data read by RFID Reader matches with any of the stored RFID Tag data inside program memory of 8051, we consider this as a Successful Access. A message “ Access Granted ” will be displayed on LCD Module. The relay will be turned ON (for 30 seconds) and hence the lamp bulb will glow indicating the door is opened. The relay will be closed after the set time (say 30 seconds) so as to prevent any further access. 2) Failed Access If the RFID Tag data read by RFID Reader does not with any of the stored RFID Tag data inside program memory of 8051, we consider this as a Failed Access. A message “ Access Denied ” will be displayed on the LCD Module. The relay will not be turned ON and hence the lamp bulb will also be kept OFF. Further Enhancements The project can be enhanced with the addition of a GSM module. A new system can be setup with the help of a GSM module to send SMS to a set of mobile numbers when someone access the system successfully or unsuccessfully (or for both events). The same system can also be modified into an RFID based Attendance management system with the addition of an RTC module and a bigger LCD display.
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