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Cordless Power Controller (CPC) is essentially a remote control implemented with the help of a cordless telephone. It has been developed as a standalone device as per the conventional DOT standards. Connecting CPC to the telephone line makes it possible to control lights, fans and other appliances of our home using our cordless phone.

The interesting feature of CPC is its ability to control two types of devices; they are ON/OFF control and ON/OFF with speed/intensity control.CPC is developed as a microcontroller 8051 based device. Which controls the devices depending on the codes entered through telephone keypad. Intensity or speed variation is obtained by altering the phase of the gate pulses given to the triac for triggering it.

Working of the CPC

1. On reset, CPC would be in the telephone mode. Power control mode (PCM) only after dialing a particular code. After the code has been entered, CPC switches to the power control mode. The indicator and the tone generator tell us that the device has been selected. And the relay disconnects telephone from the lines.

2. In the PCM, we can select different devices by dialing appropriate codes for each (For eg.1 for bulb,2 for fan ) etc.

3. After selecting a device we can control the ON/OFF state of the device by entering a different key (For eg. 3).

4. If the device selected is fan, we can con troll the speed of it by using two dedicated switches, for increasing and decreasing the speed respectively.

5. The mode changes automatically to telephone when the phone is disconnected. Thus the device works in two modes namely.