Abstract:
This Project is used to control a single phase Motor from any where in the world through the telephone. The circuit consists of a DTMF tone detector and a powerful 8 bit Microcontroller AT89S52. The Microcontroller senses the DTMF signal through the DTMF decoder IC MT8870 and it switch on/off and speed up/down the motor according to the user need. The circuit has an inbuilt Phone Ring sensor circuit and the system will take over the phone control if it was not taken manually for more than 5 rings.

The DTMF decoder decodes the DTMF tones into digital signal and this signal was fed to the Microcontroller and according to this signal the microcontroller will control the Motor with help of the TRIAC

The system is fully password protected so the user can only control the motor and the password can be changed at any time by the following method. 1. Lift the phone 2.Enter 131 old password new password new password.