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Mobile Phone alarm

Discussion in 'Electronic Design' started by JDayUK, Jun 9, 2005.

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  1. JDayUK

    JDayUK Guest

    heres my situation, im going to be having my work van kept outside my
    house soon, but its full of expensive tools etc.
    I am looking into the idea of making a mobile phone alarm. so that
    when a door is opened it triggers the phone to dial a preset number
    and alert me. the phone will be a nokia 3310. i was planning to
    connect wiring to the circuit board under the buttons.
    the way i have been planning it would work is:
    a remote operated alarm unit to control the on/off. not sure what
    output it has yet though.
    the way the phone works it will need to have one button pressed for .5
    second ( the cancel button) to clear the screen. then a 1 second pause
    and another button, ( the hot key) pressed and held for 3 seconds.
    relays should be fine to close the circuits on the buttons i think. i
    just need to get my head around the timing side of it. the circuit
    could also repeat every 30 seconds or so to make sure the message is
    any help would be much appreciated

    also i am sorry, but i posted this in basic electrics section by
    mistake, but i cant remove it, sorry, ive only just joined.
  2. Andrew Holme

    Andrew Holme Guest

    You could control the 'phone with a PIC microcontroller via an RS232
    connection to send an SMS text message

  3. Don Pearce

    Don Pearce Guest

    Much easier to manually type in the message, then click through the
    menus up to the last "send" point. Then one prod on the button from
    some suitable actuator will send the message. No need to delve into
    the phone at all.


    Pearce Consulting
  4. Zak

    Zak Guest

    Well I think he only wants his phone to ring in case of trouble. If he
    can dedicate a phone to this he may not need to activate cancel.

    If he's using a serial connection, I'd go for a Siemens phone. At least
    the 35 series (obsolete bulk market phone as is the 3310) use a 3.3 V
    CMOS level serial interface. A MAX232 is enough to talk AT commands to
    it, make it dial, send data or SMS messages. No funny software needed.

    If one is handy with PICs this must be a no-brainer.

  5. Ian Stirling

    Ian Stirling Guest

    Random thought.
    Other mobile, "voice dial" set to the sound of the alarm.
  6. JDayUK

    JDayUK Guest

    Thanks for all your replies.
    i was thinking of a fairly basic circuit originally, just a basic
    timer to press buttons in order. At the moment the phone needs to
    have cancel pressed first, as it is just a standard mobile, and
    incomming sms and phone calls may happen. when there is a missed call
    for example the hot key wont work until screen is clear and also the
    first button press doesnt do anything apart from illuminate the
    backlight, unless of course it is the cancel button, if you follow

    Also i have no experiance with PICs. I understand what they do but i
    dont know how to program them and i dont have the facilities to do

    thanks again. any further help would be great!
  7. Chris

    Chris Guest

    What about a remote door bell. I bought one recently equiv. to US$10.00 and
    has 100 metre range - true, I tested it. Battery operated to boot - both
    ends. Unless your front yard is bigger than that you may be in trouble - but
    then again if it was bigger than that you wouldn't be working.

  8. Chris

    Chris Guest

    PS. Doors aren't the only point of entry on workvans. The rubber surrounding
    the window can be removed allowing the glass to just pop out - it happened
    to me once - have a look, there is a joint in the rubber. Thieves then reach
    in and grab what they can and run off. A loud alarm at that point is the

    And keep any expensive equipment out of site by layering the storage areas.

    Just some friendly advice.

  9. JDayUK

    JDayUK Guest

    Thanks again for the replies.
    I had thought of the wireless doorbell option, then i realised that if
    i could get it to ring my phone it would be perfect, could even be set
    to ring home phone aswel.
    as for the security, its a transit with no rear windows and a
    bulkhead. so i figured that someone would either try to drive it away
    then empty it, or open it up there and then and unload it, there is
    going to be approx £2-4K of tools in the back so if someone realises
    that i will need all the security i can get. It already has a tracker
    fitted, but by the time its located it will more than likely be empty.
    as this has happened a couple of times to others.
    i have seen on the net, a SMS controller. basically a mobile is
    connected by serial port to circuit and anything can be controlled by
    TXT/SMS and it sends information/alerts/feedback to users phone. The
    downside is that its SMS only, and having experienced delays of up to
    2-3 days to recieve a txt when ideally it needs to be 2-3 seconds.

    i have some very basic ideas for a circuit using a few 555s and 4017.
    to set up a sequence like Cancel pressed 0.5s, pause 2s, number
    pressed 3s, pause (to allow to dial and connect) 30s. and the repeat.

    so would this work? a 555 in astable with delay of 3seconds, connected
    to a 4017, with first 2 outputs connected to 555s in monostable one
    with output of 0.5s and one with 3seconds. connected to relays to
    close the circuits on buttons. would the output from 4017 drive the
    555 directly? what sort of changes are needed?
  10. Zak

    Zak Guest

    And decent anti theft devices? A wheelclamp may attract attention but
    could work. So could taking parts from under the hood.
    A phone like the Siemens C/M/S35 had a built-in modem and will set up a
    call for you if you send it ATDT01234567 through its serial port (which
    is 3.3 v 'ttl' level). You can get one for a few quid. It will also send
    an SMS through that port.
    This would work as well. Also possible: make an oscillator, followed by
    the 4017. Use the outputs of the 4017 to adjust the oscillator
    frequency, so some outputs are fast and others are slow.

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