The main aim of this DTMF Based Device Controlling System project is to controlling the house holding electrical devices like fan, electrical bulb etc. From any where we can control these devices by using mobile phones. This project most useful for reducing the wastage of power; it is also useful for industrial applications. In this Engineering project we are using DTMF (Dual Tone Multi Frequency) Technology, by using this technology we can control the electrical and electronic devices.

             In this project we are using two mobile phones, micro controller, decoder, relays. One of the mobile placed at where we have controlled electrical devices (home), user can be used other mobile. The main function of this project is when user sends commands from his mobile to other mobile placed at home, after receiving commands and it transfer to DTMF signal decoder, which converts signal information into binary codes. This code sends to relays through micro controller, micro controller enable or disable the particular electrical device connects to relay.  Here the microcontroller used in this project is AT89C51, relays are used for the breaking the supply, decoder used of type 8870 chip.

Nowadays this project is most useful because of busy of human activities; it can save power and eliminates manual operation.