8051 and RFID based Access Control System - RFID Security System - RFID Access System

1. RFID Based Access Control
System using 8051
ACCESS CONTROL SYSTEM DESIGNED USING 8051
MICRO CONTROLLER AND EM-18 RFID MODULE
Submitted By: CircuitsToday

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. Project Kit – RFID Based Access Control
Project URL - http://www.circuitstoday.com/rfid-based-access-
control-system-using-8051

5. Block Diagram

6. 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 12-0-12
Others Crystal,Capacitors, Resistors, Switches, Diodes,Connectors, Power cable

7. 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.
•

8. 8051 – Internal Architecture Block Diagram

9. 8051 – Pin Diagram

10. 8051 - 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- 21-28:- 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.

11. 8051 – Reset Circuitry

12. 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

13. 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

14. 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

15. 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 Data
9 DB2 Data
10 DB3 Data
11 DB4 Data
12 DB5 Data
13 DB6 Data
14 DB7 Data
15 LED+ Back light LED+
16 LED- Back light LED-

16. Interfacing LCD Module to 8051

17. 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)

18. 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.

19. 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

20. 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

21. 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

22. 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

23. 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

24. 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.
•

25. 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

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

27. 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.

28. Project Kit – RFID Based Access Control
Project Kit URL - http://www.store.circuitstoday.com/product/rfid-
based-access-control-system-using-8051/
Circuit URL - http://www.circuitstoday.com/rfid-based-access-
control-system-using-8051