Digatal cell phone circuitry

Discussion in 'General Electronics Chat' started by Greenhorn, Aug 30, 2005.

  1. Greenhorn

    Thread Starter New Member

    Aug 30, 2005
    1
    0
    Hello, I'm working on a home project that would alow me to turn lights off in my hunting cabin that has a 12 volt power system, (i can't aford a power co. line to this place so i implemented a 12 volt system). The system is charged by an alternator system driven by an engine that utilizes propane gas that has to be manually started.
    Problem:(1) My kids use the cabin!!! They leave the lights on when they leave!!! I need to implement a cell phone system that i could call and shut the power off. My thought was to use an old phone (digital) and connect the ringer circiut to a solinoid that would accomindate 12 volts. I thought the solinoid would have to be "always on"and use the cell call to coil it off and then reset it or put it on a timer.
    Problem(2) I took the phone apart and I was beaten. I need to know if my project goal is reachable and if someone can tell me how to set it up or guide me in the right direction.
    SCOPE: I call the cell no. the phone rings at the cabin and the voltage from the ringer implements a 24 hour timer that turns off an always on solinoid that turns the power OFF!
    Thanks, inadvance to anyone who can help. GREENHORN
     
  2. Gorgon

    Senior Member

    Aug 14, 2005
    113
    0
    Hi Greenhorn,
    Do you really need to use a mobile phone to do this?

    What if you install a cheap IR-detector on a central place in your cabin. You then use the output from this to restart a timer every time somebody walks past. So when everybody leaves the retrigger stops and the timer times out after some hours. The output from this timer release a selflatched relay that is your main power supply switch. When you arrive at the cabin, just press a button to activate the relay, the timer and the IR-detector. This way you don't draw any power from the battery when the power is off, and you will always know that the power is off.

    This is not a very hi-tech solution, but it works every time, if you don't have big mice or rats in your cabin to retrigger the timer :)

    TOK ;)
     
  3. nomurphy

    AAC Fanatic!

    Aug 8, 2005
    567
    12
    Place the phone in a sealed, non-metallic, foam box with a unidirectional mic duct taped at a proper angle to the phone and wired into a "sense" circuit. When the phone rings, the mic acts as a sensor to trip your switch.

    I think Red Green would be proud of you.
     
  4. mozikluv

    AAC Fanatic!

    Jan 22, 2004
    1,437
    1
    hi,

    if you need a schem on a sound activated switch as what "nomurphy" suggested, just holler. ;)
     
  5. n9xv

    Senior Member

    Jan 18, 2005
    329
    1
    You can do this with any kind of "RF operated" remote controll. Their is a good resource at discovercircuits.com. You could use a pair of cheap CB walkie talkies to accomplish a simple carrier operated switch. If you want to get really fancy with it, youcan use a DTMF decoder board from an electronics hobby outlet etc and dial in various DTMF sequences to do different things.
     
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