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Looking for a control box

Discussion in 'Electronic Design' started by [email protected], Oct 27, 2006.

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  1. Guest


    I am looking for a box that does what I need. I would prefer to find
    one that is already being built by someone that I could buy, failing
    that I would be willing to build one (pay for one to be built) assuming
    that it isn't too horribly complicated/expensive.

    What I am looking for is a little black box with an LCD display
    (probably 2 line 40 characters or so would work), two knobs on it, and
    an ethernet connection.

    What I would like to be able to do is have the box connected to a PC
    via a router (because I plan on having multiple boxes connected) and be
    able to write some software that will monitor when either Knob A or
    Knob B has been turned on the box and which direction it has been
    turned. I would then like to be able to have the program on the PC
    update the LCD display on the box based on which knob was turned, etc.

    I would have to be able to address each box so that I could have
    multiple boxes connected to the same PC and update their LCD displays
    individually. I will need each box to send an Id of some sort when a
    knob is turned so that I know which box I am dealing with.

    Does anyone know of something like this that already exists? Even if
    it does more than I am asking and doesn't fit exactly what I need if it
    is something that could be made to do what I need that would be good
    enough for now.

    Or, do you know where I can look either to purchase something like
    this, or where I can look to find out how to build something like this
    (I have a computer background, but not an electronics background)?

    You can reply here, or send me an e-mail at bradm 6406 at h0tmail d0t


  2. Why?
  3. BobG

    BobG Guest

    You have a cost target per station? How about 8 Olimex MT128s (about
    $50 plugged into an 8 channel rs232 card?
  4. Guest

    Without giving out too much information, I basically want to be able to
    control a set of parameters in a program on a PC remotely from a simple
    (hopefully cheap) box. Dial A will scroll through a list of options
    and then Dial B will change a value associated with the option chosen
    with Dial A.

    If the box can send information to the computer giving it an ID of
    which box is currently sending the signal (could be IP based, dip
    switch setting, whatever), along with which dial is being turned, and
    which direction, and the computer can update the LCD accordingly then I
    should be able to write some software to do what I need.

    I think that building a box like this is probably not too terribly
    difficult for someone with some know-how... unfortunately I don't have
    the know-how to do it on my own. I have seen some development boards
    that I think could possibly be used to do something like this, but as I
    said... I don't really have a clue when it comes to this stuff.

    One of the boards I was looking at is from Rabbit Semiconductor:

    That board has ethernet capabilities built into it and probably more
    power than I would need. If there is something simpler that would do
    the trick that would be great.

    Are there any good resources anyone can recommend that I look at, or
    other products I should be taking a look at that might get the job

    Thanks again for any help you can provide.

  5. xray

    xray Guest

    Who's gonna write the software on the PC that monitors the source, the
    changes of knob positions, records the new data, and updates the

    Who's gonna define the protocol for the ethernet packets back and forth?
    How do you avoid collisions or loss of data? Redundancy, error checking?

    The boxes are a part of your task, but they'll never get built until you
    specify the whole system in detail.

    Or clearly specify the goal and let let engineering types propose how to
    implement it.

    With your more specific vague description maybe others might see an
    obvious easier off-the-shelf way to start.
  6. Far easier to do it via ( RS232) RS485- 4000 ft range....... Software
    overhead would be way too high with Ethernet.
  7. Joel Kolstad

    Joel Kolstad Guest

    Assuming he's going to have a protocol layer such as TCP/IP, I'd suggest it's
    no harder -- maybe even a little easier -- to use Ethernet than "raw"
    RS-232... especially if he's using a "very high" level language such as
    Python, etc.
  8. I still don't see why this isn't just a VB program.
  9. Guest

    I'm assuming and hoping that if I used a board like this:

    that it will have the tcp/ip stack built in. The board is probably
    overkill for what I need, but if the boards cost a little more but can
    get me up and running faster and save a lot of software development
    time then it will be worth it.

    To answer the question of who will be writing the software, it will
    probably be me. I am a programmer. I have never done this type of
    thing before, but assuming I don't have to write a TCP/IP stack from
    scratch I think I should be able to handle it.

    The biggest problem for me is knowing what hardware I need to buy so
    that I know I'll have a box that I can communicate with and get the job
    done. The next piece will be buying the components and getting someone
    to put them together for me. The programming is the least of my
    worries (I think... maybe that will turn out to be a lot uglier than
    I'm thinking but I hope not).

    I think I should be able to attach an LCD display, and some digital
    pots to that board and do what I need, but I'm mostly just guessing.
    I'm hoping that there is something out there that is already built so I
    don't have to build my own. Or at the very least that someone out
    there may have some experience doing something remotely similar and can
    give me a bit of advice.

    Thanks for everyone's input so far. I know it's kind of difficult to
    answer someone's questions when they don't have a clue what they're
    talking about and they're a little vague in their description of the
    problem. I can't give away all of the details on exactly what I'm
    trying to do because a friend and I are hoping to be able to build a
    product that will be worth buying when all is said and done. For now
    we just want to get a working prototype going, we can worry about
    finding simpler boards and getting things a little tidier after the
    prototype is done. We just don't want to spend a bunch of money on
    stage one doing things wrong.

    Thanks again,

  10. Jamie

    Jamie Guest

    yes, look at "RABBIT" based embedded processor boards.
    they come in a variety of packages, many of them have
    ethernet connections, along with serial connections with
    many IO lines.
    you can get stand alone Serial LCD 40x2 Row,Col displays
    that can be driven via this little RABBIT board.

    you would need the Dev package to write the code on the
    PC, it comes with examples on how to use the analog, io,
    serial, network functions..
    we use them a lot at work, make's for more compact usages
    over PLC's. most of them can fit in the parm of your hand!
  11. Guest

    The software will probably (hopefully) end up being quite simple.
    Possibly VB, Python, C#, whatever. The hard part for me is getting a
    box that can remotely send the parameters to the PC with the software
    on it, and having the PC update the LCD display on the box. I don't
    want to have the possible display values hardcoded directly into the
    box itself because I want to be able to change the possible options via
    the software.

    I basically want a very generic box that can be monitored with the
    software and can display whatever I want it to display (within the
    limitations of the LCD display that we use) based on which knob has
    been turned and in which direction.

    In the end I think a box like this could have a lot of different uses,
    but we have one specific use in mind for now.


  12. You still aren't dealing with the hardware side. If you are skilled enough,
    you could possibly do it via USB.
  13. Guest

    I think I'm having a hard time getting across what I'm trying to
    say.... or else I'm not quite understanding what you're saying.

    I will have to write software at some point, but what I am trying to
    figure out right now is what type of hardware I can use to connect to
    the PC. Either a pre-built box that I can buy from somewhere, or
    something I will have to get custom made.

    I need to have probably 6 - 8 boxes that have 2 dials and an LCD on
    them. These boxes need to be able to communicate with a PC using
    software that I will write.... later, after I know what kind of
    hardware boxes I am going to use.

    The language, protocol, etc. will all be dependant on which box I am
    able to get that will do what I need. If someone can point me to an
    ethernet box I'll write the software accordingly... if it uses USB,
    serial, infrared... whatever.

  14. IIRC, PIC ( have processors which can do IP, LCDs and USB. You
    may need one for each but they can talk to each other.
  15. John Fields

    John Fields Guest

    The way I'd do it would be to use a single rotary encoder with
    quadrature outputs and an on-board normally-open momentary
    pushbutton switch to do the manual data entry, whatever display you
    wanted to use, (two rows X 40 characters I think you said) and a
    small microcontroller to do the housekeeping. I'd use a serial port
    for communications since it's capable of full-duplex without data
    collisions, (separate TX and RX lines) and that would pretty much
    take care of the hardware.

    Want a schematic?
  16. Rich Grise

    Rich Grise Guest

    If the PC has a parellel port, it's quite easy to interface to it.

    You want a box with two knobs and an LCD, that communicates with the
    PC, right? You could do this in a 3.5" x 5" x 1.25" project box.

    I wouldn't use "knobs", though, unless you can get something like
    quadrature encoders - mouse sensors come to mind. UP/DOWN tact
    buttons could do the job, but admittedly, there are some apps
    where a knob is better. :)

    Then find a micro and LCD, drive the LCD with the micro, have it
    listen to the two knobs, and talk through a bidirectional LPT port.

    I've never heard of anything like that right off-the-shelf, although
    there are developemt boards or experimenter boards or whatever that
    have a micro, an LCD, and a monitor program. That could give you
    a starting place for proof-of-concept.

    Good Luck!
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