11-01-2013, 04:49 PM
DTMF BASED AUTOMATIC VEHICLE LOCKING
DTMF BASED AUTOMATIC VEHICLE LOCKING.pptx (Size: 1.51 MB / Downloads: 38)
PROBLEM DEFINITION
Cell phone security system is the result of a creative idea with an attempt to motivate change. Even though modern technology has allowed for the automation of many aspects of life, vehicle security system has not seen much benefit from it ,at least in India.
This project covers the use of dual tone multi-frequency generated by keypad of cell phone in locking system of vehicles. DTMF decoder decodes the signal ,sends it as an input to micro-controller which uses the input in driving the motor circuit that operates the lock.
What is dtmf?
Dual-tone multi-frequency signaling (DTMF) is used for telecommunication signaling over telephone lines. DTMF is the global standard for audible tones that represent the digits on a phone keypad with touch-tone , pressing a key on the dial pad generates the corresponding DTMF tone for that key. The land-line phone system can then "listen" and decode that tone to determine which key was pressed enabling dialing.
The DTMF keypad is laid out in a 4×4 matrix, with each row representing a low frequency, and each column representing a high frequency. Pressing a single key (such as '1' ) will send a sinusoidal tone for each of the two frequencies (697 and 1209 hertz (Hz)).
L293D MOTOR DRIVER
L293D is a dual H-Bridge motor driver, so with one IC we can interface two dc motors which can be controlled in both in clockwise and anticlockwise direction and if you have motor with fix direction of motion. You can make use of all the four I/Os to connect up to four DC motors, L293D has output current of 600 mA and peak output current of 1.2A per channel. Moreover for protection of circuit from back EMF output diodes are included within the IC. The output supply (VCC2) has a wide range from 4.5 to 36V, which has made L293D a best choice for DC motor driver.
OTHER HARDWARE COMPONENTS
LCD DISPLAY:-A 16x2 LCD contains 16 pins.
The first row of the LCD starts with the
address 8xH where ‘x’ stands for column number. Similarly the second is referred
by the address CxH. The value ‘x’ varies from 0 to F for 16 columns.
NUMERIC KEYPAD:-A numeric keypad is a matrix of keys arranged into 3 columns and 4 rows. Intersection of each row and column is a push switch. Pressing the switch forms contact between that particular row and column. So, 12 unique contacts are present in a 4x3 keypad. Corresponding to each contact there is a unique function assigned during programming the microcontroller, such that the microcontroller recognizes which key has been pressed and acts accordingly.
BUZZER SYSTEM:- A buzzer or beeper is an audio signaling device, which may be mechanical, electromechanical, or piezoelectric. Typical uses of buzzers and beepers include alarm devices, timers and confirmation of user input such as a mouse click or keystroke.
GEARED DC MOTOR :- Geared DC motors can be defined as an extension of DC motor which has a gear assembly attached to the motor. The speed of motor is counted in terms of rotations of the shaft per minute and is termed as RPM .
The gear assembly helps in increasing the
torque and reducing the speed.