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Mobile incoming call indicator

Mobile incoming call indicator

Mobile incoming call indicator

By admin

Description.

This circuit can be used to escape from the nuissance of obile phone rings when you are at home.This circuit will give a visual indication if placed near a mobile phone even if the ringer is deactivated.

When a call is coming to the mobile phone, the transmitter inside it becomes activated.The  frequency of the transmitter is around 900MHz.The  coil L1 picks up these oscillations by induction and feds it to the base of Q1.This makes the transistor Q1 activated.Since the Collector of Q1 is connected to the pin 2 of IC1 (NE555) , the IC1 is triggered to make the LED connected at  its output pin (pin 3) to blink.The blinking of the LED is the indication of incoming call.

 

Circuit diagram with Parts list. 

 mobile-incoming-call-indicator-circuit.JPG

 

Notes. 

  • The coil L1 can be made by making 150 turns of 36 SWG enameled copper wire on a 5mm dia plastic former.Or you can purchase a 10 uH coil from shop if available.
  • The circuit can be powered from a 6V battery.
  • Assemble the circuit on a good quality PCB.
  • C1 & C3 are to be polyester  capacitors.
  • The electrolytic capacitor C2 must be rated 10V.

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October 5, 2009 - Posted by | project ideas, SENSORS

3 Comments »

  1. circuit not working properly
    led is glowing when iam connecting d circuit with battery
    its not glowing fully but showing fluctuation
    n when mobile is kept beside d circuit
    nothin is hapenning
    what to do ?

    Comment by amit | January 11, 2010

  2. ANY THING COULD ONLY BE SAID AFTER CHECKING THE CIRCUIT PLEASE GET UR CIRCUIT CHECKED OR TESTED SOMEWHERE.

    Comment by IndianEngineer | January 11, 2010

  3. led glows without d call also, i evn tried removing D1, den led doesn’t glow at all. plzz, help

    Comment by rj | March 25, 2013


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