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Using DTMF to drive solenoids

Discussion in 'General Electronics' started by Eibert Draisma, Jul 25, 2005.

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  1. Dear All,

    I am new to DTMF as well as to this group so forgive me in case
    of "stupid" questions...

    I am looking for hardware to control 16 solenoids using DTMF tones.
    In fact I am building an instrument consisting of 16 automated

    My goal is to find a solution as simple as possible to drive the

    My basic idea is:
    1) Use a MP3 player to store a "song" consisting out of differtent DTMF
    2) Use a simple DTMF receiver connected to the MP3 player to detect the DTMF
    (e.g. MT8870D / MT8870D-1 Integrated DTMF receiver)
    3) Use simple electronics connected to the DTMF receiver to drive 16
    (Solenoids: 12VAC or 12VDC)

    Does anyone of you know a simple approach to do this?
    I know just enough about electronics to build a simple schematic.

    I really hope anyone of you can give me some help!

    Best regards,
    Eibert Draisma.
  2. John Fields

    John Fields Guest


    Do you plan to drive the solenoids mutually exclusively, (only one on
    at a time) or will you be driving more than one simultaneously?

    Do you want the solenoid(s) to latch on and off, or will they only be
    on when their DTMF tone pairs are hot?
  3. Tom Biasi

    Tom Biasi Guest

    You certainly need to consider the questions of John Fields but may I ask,
    why do you want to take the DTMF approach?
    You may find the decoding time is too slow for your application. There are
    many digital schemes that can do what you want.
  4. Dear John,

    My idea was to drive one solenoid at a time; I can imagine driving more
    solenoids (each related to a specific DTMF tone) simultaneously would result
    in problems concerning the decoding?
    The solenoids should only be "on" when their DTMF tone pairs are hot; I
    simply would record a "DTMF-tones song" and store it on a MP3 player.

    What do you think; would this work?

    Eibert Draisma.
  5. Owamanga

    Owamanga Guest

    Castagnettes being two small wooden paddle things tied together with a
    piece of string? - Like the flamenco dancers use?

    You want to automate 16 small wooden percussion instruments?

    ....hmm...this isn't going to sound good, is it?
  6. John Fields

    John Fields Guest

    Yeah, it'll work fine if, as Tom Biasi noted, you can take the delays.
    Something like 40 or 50ms from the time DTMF ocurs on the decoder
    input until the decoded outputs go true, and about the same, I think,
    for the release. In any case it's on the data sheets.

    Just as an aside, why do you want to use DTMF?
  7. I don't care about the delays as this concerns a stand alone instrument;
    performing only now and than when it feels like performing...

    The only reason I wanted to use DTMF is I think the electronics can be
    cheap. (I don't need all kind of advanced midi possibilities)
    Besides this I would like to keep the circuitry as simple and compact as

    Do you think this is the right approach?

    Eibert Draisma.
  8. No, this is not going to work. The delay's for DTMF are to
    big to do ritmitical things like castagnettes. The delay's
    should not be bigger than 10 mSec.

    What you should do is tell us what you want to do, then
    people can give sugestions instead of you giving solution
    while we don't understand the real problem.

    Good luck,

    NB. (and you shouldn't crosspost to 6 groups
    comp.robotics.misc should be enough).
  9. John Fields

    John Fields Guest

    It sounds fine to me, and here's how I'd do it:

    |K |
    [1N4001] [SOLENOID 16]
    | |
    Vcc |
    | +--------+ C
    +---------+ +---|LE Q15|--[R16]--B Q16
    DTMF>---|Vin Q4|---------|A3 Q14| . E
    | Q3|---------|A2 Q13| . |
    | Q2|---------|A1 Q12| . GND
    | Q1|---------|A0 Q11| .
    | | |\ |_ Q10| .
    | StD|--| >O--O|E Q09| . +V
    +---------+ |/ | Q08| . |
    MT8870 | Q07| . +----------+
    | Q06| . |K |
    | Q05| . [1N4001] [SOLENOID1]
    | Q04| . | |
    | Q03| . +----------+
    | Q02| . |
    | Q01| . C
    | Q0|--[R1]---B Q1
    +--------+ E
    HC4514 |

    If you know what solenoids you want to use (or their actuation
    current) I can recomment suitable MOSFET or bipolar driver transistors
    and base resistors. Also, if you don't need more than the one
    inverter on the ENABLE input of the 4514, it would be easy to
    sustitute a transistor and save a chip.
  10. steamer

    steamer Guest

    --Sill me; what is DTMF?
    --I'm using solenoids as well, via Stamp, but to control a (fairly
    primitive) tap-dancing robot.
  11. John Fields

    John Fields Guest

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