Mobile Phone Keypad Sensed Password Entry For Door Opening

Mobile phone keypad sensed
password entry for door opening

http://www.edgefxkits.com/
Introduction
 The main objective of this project is to unlock the door using cell
phone.
 A unique password must be entered through the keypad of cell
phone to unlock the door.
 Each key of the password is identified with a frequency which is
decoded to digital code through DTMF (digital tone multi frequency)
decoder and that code is fed to a microcontroller which is
programmed to recognize the code for operating the door duly
interfaced through motor driver and finally the password is checked
whether it is correct or not.

Block Diagram

Working of this Project:
 The mobile is connected to the DTMF decoder IC and a call is made
to data mobile from another mobile.
 When the network path is formed, any mobile key is pressed.
 If 1 is pressed then this tone is decoded to 4 digit data and given to
MC by inverting the data.
 MC compares this data and at output port which is connected to
ULN gets logic high and the output of ULN is low which makes the
relay ‘ON’. Hence, load 1 will be ‘ON’.

Hardware requirements
 POWER SUPPLY
 MICROCONTROLLER 8052
 Dual Tone Multi Frequency
 MOTOR DRIVER IC

230 V AC
50 Hz
Bridge rectifier
Filter(470µf)
5v Regulator
5V DC
12V step down
transformer
Power supply

Dual Tone Multi Frequency
 HT9170 is the series of Dual Tone Multi Frequency (DTMF) receivers.
They employ digital counting techniques to detect and decode the
16 DTMF tones into 4 bit output code.
 HT9170 series receivers do not require any external filters as they
use highly accurate switched capacitor filters for filtering low and
high frequency signals from the DTMF tones. They also support
power down (PWDN) and inhibit (INH) modes. PWDN mode is used
to power off the crystal, while INH mode to inhibit the A, B, C & D
DTMF tones. The clock is provided by a 3.58 MHz crystal.
 In simple terms, HT9170 IC detects and decodes the 16 DTMF tones
into 4 bit output. In case the tones are not detected, the four output
bits remain low. The DV pin goes high on detection of a valid tone.

DTMF Diagram

 8K Bytes of In-System Programmable (ISP) Flash
Memory.
 4.0V to 5.5V Operating Range.
Crystal Frequency 11.0592MHZ.
 Three-level Program Memory Lock.
 256 x 8-bit Internal RAM.
 32 Programmable I/O Lines.
 Three 16-bit Timer/Counters.
AT89S52
Micro controller

CPU
On-chip
RAM
On-chip
ROM for
program
code
4 I/O
Ports
Timer 0
Serial
PortOSC
Interrupt
Control
External interrupts
Timer 1
Timer/Count
er
Bus
Control
TxD RxDP0 P1 P2 P3
Address/Data
Counter
Inputs
Block diagram of MC

MC components explanation
ROM:
 A code of 4K memory is incorporated as on-chip ROM in 8051.
RAM:
 The 8051 microcontroller is composed of 128 bytes of internal RAM.
Interrupt Control:
 An event which is used to suspend or halt the normal program
execution for a temporary period of time in order to serve the
request of another program or hardware device is called an
interrupt.

Parallel Input/Output Ports:
PORT P0: When there is no external memory present, this port acts as
a general purpose input/output port.
PORT P1: This port is used for various interfacing activities.
PORT P2: This port can be used as a general purpose port when there
is no external memory but when external memory is present it works
in conjunction with PORT PO as an address bus.
PORT P3: PORT P3 behaves as a dedicated I/O port.

Address Bus:
 A bus is group of wires using which data transfer takes place
from one location to another within a system.
Timers and Counters:
 Synchronization among internal operations can be achieved with
the help of clock circuits which are responsible for generating
clock pulses.
 Internal operations can be synchronized using clock circuits
which produce clock pulses.

Pin diagram of 8052

8052 pin diagram explanation
Port 0(p0.0 to p0.7):
 It is 8-bit bi-directional I/O port. It is bit/ byte addressable. During
external memory access, it functions as multiplexed data and low-
order address bus AD0-AD7.
Port 1 (p1.0 to p1.7):
 It is 8-bit bi-directional I/O port. When logic '1' is written into port
latch then it works as input mode. It functions as simply I/O port
and it does not have any alternative function.

8052 pin diagram explanation
Port 2 (p2.0 to p2.7):
 It is 8-bit bi-directional I/O port. It is bit/ byte addressable.
Port 3(p3.0 to port 3.7):
 It is 8-bit I/O port. In an alternating function each pins can be used
as a special function I/O pin.
RESET:
 It is active high I/P signal. It should be maintained high for at least
two machine cycle while oscillator is running then 8051
microcontroller resets.

Motor driver IC
 L293D is a dual H-bridge motor driver integrated circuit (IC).
 Motor drivers act as current amplifiers since they take a low-
current control signal and provide a higher-current signal.
 This higher current signal is used to drive the motors.
 L293D contains two inbuilt H-bridge driver circuits. In its
common mode of operation, two DC motors can be driven
simultaneously, both in forward and reverse direction.

Motor driver ic diagram

Operation of motor driver
 L293D has 2 set of arrangements where one set has input 1, input
2, output 1 and output 2 and other set has input 3, input 4,
output 3 and output 4, according to block diagram if pin no 2 & 7
are high then pin no 3 & 6 are also high.
 If enable 1 and pin number 2 are high leaving pin number 7 as
low then the motor rotates in forward direction.
 If enable 2 and pin number 10 are high leaving pin number 15 as
low then the motor rotates in forward direction.

Operation of motor driver
 If enable 1 and pin number 2 are low leaving pin number 7 as
high then the motor rotates in reverse direction.
 If enable 2 and pin number 15 are high leaving pin number 10
as low then the motor rotates in forward direction.

Operational diagram

Software requirements
 Keil an ARM Company makes C compilers, macro assemblers,
real-time kernels, debuggers, simulators, integrated
environments, evaluation boards, and emulators for
ARM7/ARM9/Cortex-M3, XC16x/C16x/ST10, 251, and 8051 MCU
families.
 Compilers are programs used to convert a High Level Language to
object code. Desktop compilers produce an output object code
for the underlying microprocessor, but not for other
microprocessors.

Applications
 This project can be applicable in offices, banks and also at home.
 It will provide keyless entry to the users.
 Frequent carrying of keys is not required for the users.
 User friendly digital code lock.

Conclusion
 This PPT presentation describes about the project “Mobile Phone
Keypad Sensed Password Entry for Door Opening”, a safety technique
to unlock the door using cell phone.
 The goal of this work is to design and implement a high technology
security to access proper door system using mobile phones at ease.

Mobile Phone Keypad Sensed Password Entry For Door Opening

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Mobile Phone Keypad Sensed Password Entry For Door Opening