Telephone Controlled Remote Switch

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Abstract:
This Project is used to control our household electrical devices from any where through the cell phone. The circuit consists of a DTMF tone detector and a powerful 8 bit Microcontroller AT89S52. The microcontroller controls all the system. In this project we control total six devices.

The Microcontroller senses the DTMF signal through the DTMF decoder IC MT8870 and it switch on/off the corresponding devices 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.Press the corresponding numbers to turn on/off the devices, for ex: press 1 to turn on/off device 1, press 0 to switch off all devices, press 9 to switch on all devices, press 8 to disconnect the telephone.