DTMF SIGNALLING CODED SYSTEM AT ROTATING MOVEMENT CONTROLLER OF MONITORING CAMERA

Abstract

Signalling System of DTMF is coding in the form of tone converted into a binary
number from the use of the combination of dual tone /frequency produced by
pressing the tone of telephone. The use of dual tone is meant for the dialing that is
not interrupted by other frequency, with the frequency limitation that is used in the
range of telephone operator. This coded system will be the inputted signal that can
move the motor in contolling the rotating of the camera. In this system, the
performance of DTMF signal sent by transmitted telephone tone is being inputted
to the IC MT8870 as the signal interpreting of DTMF, whereas every DTMF
inputted signal has their own frequency range. Then, that signal will become the
input of IC decoder 74LS4514 which will interprete the voltage changing, after
that, it is inputted to the IC microcontroller AT89C52 in the form of binary. The
output of this IC will activate driver that will move the relay of loads’ controller.
From the measurement of DTMF output when being given interruption, the
frequency of pressed tone “2” is 1145 Hz, pressed tone “4” is 1135 Hz, pressed
tone “6” is1477 Hz, and pressed tone “8” is 1059 Hz.