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Controlling a circuit via SMS

Discussion in 'Electronic Design' started by [email protected], Sep 27, 2005.

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  1. Guest

    Hi folkes,

    I wish to switch on and off a circuit via SMS (text messaging). I'd
    also be interested in sending messages directing when and for how long
    the circuit should be switch on for. To do this, am I right in saying
    that I need a GSM module and a microcontroller? What model of GSM
    module would you recommend?

    Lets say I wished to complicate things further by adding a LCD display,
    in order to show the status of the circuit (whether on or off, if it is
    scheduled to come on etc), what kind of contoller would be suitable in
    this case?

    I was also thinking that it might be necessary to include a key pad.
    This would allow the user to enter the mobile number that the circuit
    should respond to (stop others interfering with the circuit). Or the
    keypad could be used for entering a pin number for the device, and this
    pin would be requested in order for the user to be granted access to
    switching on and off the system via their phone.

    So to sum up, I think I'm right in saying that I need a GSM module, a
    microcontroller, a keypad (12 keys should be more than enough) and a
    LCD display (20 x 4 LCD module perhaps?). Can you recommend me models
    for these 4 devices as I'm not at all familiar with this area and there
    is so many devices out there.

    Any other advice?

    Thanks very much for your help,

  2. I read in that wrote (in
    We don't tell people how to switch things on with mobile phones, in case
    they go BANG!
  3. Tom

    Tom Guest

    Have you considered using a normal GSM phone that can be controlled
    over a data cable?

    The article at
    discusses something like that using an Ericson phone, but I would
    expect a similar method to work for other brands also.

  4. Genome

    Genome Guest

    Yes, don't call me 'folkes', don't even call me 'folks'.

    If I want to microwave a tin of beans then there is a procedure I go through
    to get the job done.

    Part of that procedure does not involve calling someone else up on my mobile
    phone and saying 'Tin of Beans, 5 minutes'.

    **** Off

  5. George Bush

    George Bush Guest

    STFU, asshat
  6. Donald

    Donald Guest

    Google for SMS controllers, and you will find a few projects.

    As long as you are not in North America.

    I have yet to find a carrier that will allow you to get serial data from
    a regular cell phone.

    But you can buy special radio modems that offer SMS service.

  7. Pooh Bear

    Pooh Bear Guest

    You're a bomb maker ?

  8. Guest

    You're a bomb maker ?

    I'm actually a student looking for some ideas for my final year
    project. I was thinking of a remote controller that would allow people
    to turn on and off their home heating system. This would facilitate
    people in turning off their heating if they were delayed at work for
    example, and set it for a later time. I didn't anticipate for a second
    that there would have been such a paranoid response to my question. You
    do all realise that if someone wants to kill someone it doesn't require
    any degree of imagination or sophistication. Where there's a will,
    there's a way. I don't see why terrorists should be given a monopoly
    over technology, while people like myself are made to feel stupid for
    asking simple, straightforward questions. Some of you people are
    playing right into the hands of terrorist by helping them in their
    mission to spread fear and paranoia to our society.

    Anyway, thanks for those who did reply in a constructive fashion. I've
    come across this very useful article -

    SMS Controller, Part 1:
    SMS Controller, Part 2:
    SMS Controller, Addons:

    The microcontroller referred to in this article is the AT90S8515. Would
    it be capable of controlling a small keypad and a small lcd display
    also do you think?


  9. I read in that wrote (in
    It's not paranoid. Don't be rude to your elders.
    Not all potential bombers are highly-educated or inventive. Some would
    indeed be stupid enough to ask on a newsgroup how to construct a bomb.
    There is, after all, quite a lot of relevant information elsewhere on
    the Internet.

    If you'd explained about being a student, and wanting to do a project,
    by the way, that's been done by thousands of students over the past 20
    years or so, so is a mite unoriginal, you might have received fewer
    suspicious replies.
  10. Guest

    It's not paranoid. Don't be rude to your elders.

    If Barry is being rude, then John you are being both pompous and
    boorish to the extreme. Clearly the question was left open because the
    student hasn't yet settled on the exact application he wishes to
    proceed with. And as for paranoia, do we now have to state our
    profession in order to receive a satisfactory answer to our questions?
    You do realize that the London bombers were students at a Leeds
    university? Not that they actually used SMS. I'm also sure a bomber
    could manage to go online and pretend he was a student, no?

    Barry, that microcontroller should work fine for what you wish to
    achieve. Have you chosen a supervisor yet? If not, find a lecturer with
    experience in the control field and talk to them about your idea. Your
    supervisor might well have an area of expertise which SMS control could
    be applied to. You might also have a look at Maxim's microlan
    devices. These include temperature sensors/loggers and ADCs etc, which
    can be organized on a simple 1-wire network.
  11. Peter K

    Peter K Guest

  12. Silicon Chip did a project on this:

    Dave :)
  13. These ;-)

    The bumf sez:
    The GT47/GT48 can be configured to independently perform control and
    alarming functions using a built-in scripting engine, minimizing the need
    for extra components. This means the GT47/GT48 can be programmed to
    communicate with the connected asset intuitively, therefore enabling users
    to add metering, and other local control functions as required. The outcome
    is a more customized, efficient, and costeffective M2M application.

    What you want, not?

    Siemens does/did a Linux-based development board too - around USD200,
    colleague bought it for fun - but their crap website defies any attempt at
    locating actual products!! So that's some homework for you.
    Use the one that's inside the Kit.

    The small Epson/Seiko LCD's are easy to drive once one (eventually) gets the
    critical timing requirements and the undocumented character memory layout
    right. Or use an embedded PC as an ASCII terminal and gloss it up with one
    of the interfaces/GUI's that comes with Linux.
    I think your life would be easier if you use "encrypted command strings over
    SMS" purely as the signalling protocol and then use one of the advanced
    mobile handsets to handle the actual communication with the user - the
    Java-enabled handsets in general have good free-of-charge development
    systems for them. The sucessful decryption of a command is the validation.
    The crypto can be made as strong as you care to wait for it. The problem
    with PIN codes is that either you have to enter it with each command or you
    have to have some protocol to deal with the asyncronous nature of texting -
    i.e. Which command are you validating Now? If you think that is not a
    problem, then look at the perpetual brokeness of SNMP implementations and

    You should certainly check if there actually is access to the SMS engine in
    software, in *many* cases all you get is HTTP 1.1 with J2ME and you need a
    Binary/Native application instead (the Mobile Games development kits is
    where one finds the gratis development systems for native applications).
    When asking question on News, Specify what you want TO ACHIEVE in DETAIL -
    Do you merely want to BUILD a GSM M2M controller or do you want to USE the
    functionality for .... WHAT, exactly. Someone might have done it already,
    and know some extra things to look out for.

    You - and everybody else - will get better answers that way!!
  14. Thinking a bit more:

    *If* you get a GPRS M2M module, wich will have always-on TCP/IP anyway and a
    half-decent CPU to boot, why not have it serve up a WEB page with the
    controls of whatever you want to do, including access control and
    validation? Or stick an embedded Linux box at the end of it for about as
    much power as you want to pay for.

    That will work with *anything* on the planet and reduce the programming task
    to the Server side. The client does HTTP anyway. Does away with the need for
    a special SMS interface too.

    .... And Users WANT pretty pictures!!
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