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    HOME AUTOMATION USING PHONE (DTMF TOUCH-TONE)

    7805 ic labels are reversed, I will clear it. at board 3 there should be 4.7K replaced with 470 Ohm and a 1K preceding all LEDs.
  2. V

    HOME AUTOMATION USING PHONE (DTMF TOUCH-TONE)

    Here I am presenting my final mini-project setup. See the attachment in this forum or the link... http://www.scribd.com/doc/29233455 I express my sincere thanks to all forum members for there great support without whom this project wouldn't have been a reality. Still I am welcoming new ideas...
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    some weird effect of Telephone DTMF MT8870CE !!!

    Look up the attachment . http://www.scribd.com/doc/27392525 When power up the circuit all LED s 1 to 4 turned-on (I expect all turn-off). The problem is that, When I calling from remote end all the LED s blinking randomly for 1 sec (undesired result) and then  comes to a stable state. But...
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    Efficient telephone audio (300-650Hz) fedback mechanism !!!

    I think all these problems can be solved by using RC or wein bridge oscillator at audio frequency. Thus replacing square pulses with sine waves. 10k will be replaced with 470 ohm at coupling path. What about my prediction ???
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    Efficient telephone audio (300-650Hz) fedback mechanism !!!

    Can anybody suggest any efficient audio fed-back mechanism through telephone line so that the telephoning person can hear audio beeps, by which he can check the status of remotely controlled device (teleremote control). I have tried two circuits (see two attached files)...
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