Mobile phone keypad sensed password entry for door opening
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.
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Block Diagram
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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’.
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Hardware requirements POWER SUPPLY MICROCONTROLLER 8052 Dual Tone Multi Frequency MOTOR DRIVER IC
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Power supply
230 V AC 50 Hz
Bridge rectifier
5v Regulator 5V DC Filter(470Âľf)
12V step down transformer
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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. http://www.edgefxkits.com/
DTMF Diagram
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Micro controller 8K Bytes of In-System Programmable (ISP) Flash Memory. 4.0V to 5.5V Operating Range. Crystal Frequency 11.0592MHZ.
AT89S52
Three-level Program Memory Lock. 256 x 8-bit Internal RAM. 32 Programmable I/O Lines. Three 16-bit Timer/Counters.
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Block diagram of MC External interrupts Interrupt Control
On-chip ROM for program code
Timer/Count er
On-chip RAM
Timer 1 Timer 0
Counter Inputs
CPU
OSC
Bus Control
4 I/O Ports P0 P1 P2 P3
Serial Port
TxD RxD
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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. http://www.edgefxkits.com/
MC components explanation 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. http://www.edgefxkits.com/
MC components explanation 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. http://www.edgefxkits.com/
Pin diagram of 8052
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8052 pin diagram explanation Port 0(p0.0 to p0.7): ďƒ˜ It is 8-bit bi-directional I/O port. It is bit/ byte addressable. During external memory access, it functions as multiplexed data and loworder address bus AD0-AD7. Port 1 (p1.0 to p1.7): ďƒ˜ 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.
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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. http://www.edgefxkits.com/
Motor driver IC L293D is a dual H-bridge motor driver integrated circuit (IC). Motor drivers act as current amplifiers since they take a lowcurrent 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.
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Motor driver ic diagram
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Operation of motor driver ďƒ˜ 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. ďƒ˜ If enable 1 and pin number 2 are high leaving pin number 7 as low then the motor rotates in forward direction. ďƒ˜ If enable 2 and pin number 10 are high leaving pin number 15 as low then the motor rotates in forward direction.
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Operation of motor driver ďƒ˜ If enable 1 and pin number 2 are low leaving pin number 7 as high then the motor rotates in reverse direction. ďƒ˜ If enable 2 and pin number 15 are high leaving pin number 10 as low then the motor rotates in forward direction.
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Operational diagram
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Software requirements ďƒ˜ 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. ďƒ˜ 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.
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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.
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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.
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