25-07-2012, 04:21 PM
HOME AUTOMATION CONTROL SYSTEM USING DTMF
41266595-Home-Automation-Control-System-Using-Dtmf.ppt (Size: 1.39 MB / Downloads: 75)
introduction
One can access this unit even when he/she is not present at the place where the system is installed.
Any (DTMF) telephone set or hand-held tone dialer may be used to send commands to the switching unit.
The switching unit is capable of controlling mains, powered loads with the aid of commands received via a telephone.
What is DTMF ?
Dual tone multiple frequency signaling (DTMF).
Multiple-frequency signaling consists of a combination of two tones with frequencies within the speech band.
Each combination of two frequencies representing a single digit.
System Working
Dial your number using DTMF phone or Cell phone from anywhere in the world.
The MCU on the interface senses Telephone ring, Automatic telephone pick up, and line hang up, displays information on a 16x2 LCD module and controls the relay switching.
After a six rings the circuit lifts the receiver and sends an acknowledgement tone to signal to the caller that a six-digit password number is to be entered.
Microcontroller unit works
To count the pre-programmed number of ringing signals.
To enable the high value resistance after counting the pulses.
To accept the decoded tones send by the tone decoder.
To operate the corresponding relays according to the signals.
applications
Wide range of applications in various fields
Household applications
Industrial applications
Office applications
Institutional applications
Telephone answering machine
Interactive voice response system(IVRS)