1. RFID Based Access Control System using 8051
Access control system designed using 8051 micro controller and em-18 RFID module
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2. Table of Contents Project Objective Block Diagram Hardware Components
Component Descriptions
Software Requirements
Working Model
Applications
Enhancements
Conclusion

3. Project Overview Provide security to organizations
Access allowed only to authorized personnel with a valid RFID tag
Designed using 8051 micro controller and EM-18 RFID module
Status messages are displayed on 16x2 LCD module
Output controlled via DC relay.

4. Block Diagram

5. Hardware Components Component Specification Microcontroller
8051 Series (AT89S51)
RFID Reader
EM-18 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
Others
Crystal,Capacitors, Resistors, Switches, Diodes,Connectors, Power cable

6. Microcontroller - 8051 AT89S51 – is the 8051 variant from Atmel
A micro controller is an integrated circuit or a chip with a processor and other support devices like program memory, data memory, I/O ports, serial communication interface etc integrated together.

7. 8051 – Internal Architecture Block Diagram

8. 8051 – Pin Diagram

9. Pin Descriptions
Pin-40 : Named as Vcc is the main power source. Usually its +5V DC.
Pins 32-39: Known as Port 0 (P0.0 to P0.7) – In addition to serving as I/O port, lower order address and data bus signals are multiplexed with this port (to serve the purpose of external memory interfacing). This is a bi directional I/O port (the only one in 8051) and external pull up resistors are required to function this port as I/O.
Pin-31:- ALE aka Address Latch Enable is used to demultiplex the address-data signal of port 0 (for external memory interfacing.)  2 ALE pulses are available for each machine cycle.
Pin-30:- EA/ External Access input is used to enable or disallow external memory interfacing. If there is no external memory requirement, this pin is pulled high by connecting it to Vcc.
Pin- 29:- PSEN or Program Store Enable is used to read signal from external program memory.
Pins :- Known as Port 2 (P 2.0 to P 2.7) – in addition to serving as I/O port, higher order address bus signals are multiplexed with this quasi bi directional port.
Pin 20:- Named as Vss – it represents ground (0 V) connection.
Pins 18 and 19:- Used for interfacing an external crystal to provide system clock.
Pins 10 – 17:- Known as Port 3. This port also serves some other functions like interrupts, timer input, control signals for external memory interfacing RD and WR , serial communication signals RxD and TxD etc. This is a quasi bi directional port with internal pull up.
Pin 9:- As explained before RESET pin is used to set the 8051 microcontroller to its initial values, while the microcontroller is working or at the initial start of application. The RESET pin must be set high for 2 machine cycles.
Pins 1 – 8:- Known as Port 1. Unlike other ports, this port does not serve any other functions. Port 1 is an internally pulled up, quasi bi directional I/O port.

10. 8051 – Reset Circuitry

11. RFID Reader Module
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

12. 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
Unique RFID key – read by an RFID Reader
Comes in many shapes – smart cards, key tags, buttons etc
comes with a chip with memory to store RFID identification code, a coil and a modulator.
coil is to energize the chip via electro magnetic induction
modulator modulates the RFID code/key according to the frequency
Coil also serves as an antenna to transfer information in air medium

13. LCD Module 16×2 LCD module - consists 16 rows and 2 columns
Model – Hitachi JHD162A
comes in a 16 pin package with back light ,contrast adjustment function

14. 16x2 LCD Module – Pin Description
Pin No:
Name
 Function 1
VSS
This pin must be connected to the ground 2
VCC
 Positive supply voltage pin (5V DC) 3
VEE
Contrast adjustment 4 RS
Register selection 5
R/W
Read or write 6 E
 Enable 7
DB0
 Data 8
DB1 9
DB2 10
DB3 11
DB4 12
DB5 13
DB6 14
DB7 15
LED+
 Back light LED+ 16
LED-
 Back light LED-

15. Interfacing LCD Module to 8051

16. Relay 12 Volts DC Relay (SPDT – Single Pole Double Throw)
A relay is an electrically operated switch
Relays allow one circuit to switch a second circuit which can be completely separate from the first.
Example: a low voltage battery circuit can use a relay to switch a 230V AC mains circuit.
There is no electrical connection inside the relay between the two circuits, the link is magnetic and mechanical.
A relay needs a driver circuit (which provides necessary current).
Relay driving circuit can be designed using a transistor (2N2222) or an IC (ULN2003)

17. Relay – Connections and Operation
Current flowing through the coil of the relay creates a magnetic field which attracts a lever and changes the switch contacts.
The coil current can be on or off so relays have two switch positions and have double throw (changeover) switch contacts as shown in the diagram.

18. 7805 – 5V Regulator 5V supply is essential for 8051 and RFID module
Input voltage range 7V- 35V
Current rating Ic = 1A
Output voltage range   VMax=5.2V ,VMin=4.8V
Heat Exchange is necessary if input voltage is higher

19. 7812 – 12V Regulator 12V supply is essential for the 12V DC relay
Input voltage range 14V- 35V
Current rating Ic = 1A
Output voltage range   VMax=12.2V ,VMin=11.8V

20. W10 – Bridge Rectifier
Bridge rectifier is used to convert AC supply (from step down transformer) to DC supply
To reduce size of circuit, a single unit bridge rectifier – W10 is used

21. 2N2222 – Transistor
2N2222 is a common NPN bipolar junction transistor (BJT) used for general purpose low- power amplifying or switching applications
Used to drive relay in this application by providing appropriate current amplification

22. Software Requirements
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 (MCS-51 instruction set) or Embedded C|Compiler: Keil or MIDE-51

23. Working Model
We store a set of RFID tag data (unique RFID codes/keys) inside our program/system, say 3 or 10 RFID tag data
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 come and swipes his RFID tag near the RFID reader, access will be granted.
When the person with the wrong RFID card swipes his RFID tag, access will be denied.
The 16x2 LCD module will display different status messages.

24. Expected Outputs
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.
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 match 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

25. Applications Manufacturing Supply Chain, Logistics & Distribution
Security And Access Control
Parking, Bay And Terminal Management
Tool Collection

26. 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.

27. End!
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