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Visible metronome for Groups.

Discussion in 'Electronic Basics' started by Somebody, Feb 17, 2008.

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  1. Somebody

    Somebody Guest


    Does anyone on this group know of a device which I could plug into the
    jack plug of a digital metronome that could be used to control a light
    of some sort? I want to attempt constructing a visible metronome for
    our community percussion project. Sadly we're so loud there's no
    chance of us being able to hear any sort of click track and I can't
    seem to find anything suitable on the market. I have quite a few
    metronomes, all which generate a signal for head phones. How hard
    would it be to use that signal to make a large bulb flash?


    (Sorry - complete electronics ignoramus but worth a try none the less.)
  2. Chris W

    Chris W Guest

    Why not just search for a strobe light. They often have the ability to
    vary the frequency of flash over a wide range, not need to use an
    existing metronome as the signal source.

    found this in 2 min on google...

    Chris W

    "Protect your digital freedom and privacy, eliminate DRM,
    learn more at"

    Ham Radio Repeater Database.
  3. JeffM

    JeffM Guest

    Does anyone on this group know of a device
    Always investigate the *buy* route first.
    Your first move should have been
    using one of Google's numerous specialized search engines:

    *Product Search*
    This appears to meet your spec:

    Scroll down ~80%,200W+Rope.Light.Controller
    I don't see a spec for its lower limit for standalone flashing speed,
    but it may even do the job unassisted.
    In contrast to Chris's suggestion, this can use standard incandescents
    and you can place numerous indicators in various lines of sight.

    More vendors:
  4. But isn't the drum supposed to keep the beat, in which case you
    ought to have a good drummer that is the one for the rest to follow.

    Or get a drum machine, and have it keep the beat.

    I can't help but wonder if a visual signal will be an issue. It's
    easier to copy morse code when it's sent as sound than as a light,
    and that makes me think there may be a lag for drummers trying to follow
    a visual beat.

    So if a good drummer or drum machine doesn't work, run a metronome
    to an audio amplifier, and then feed that to a single headphone for
    each of the drummers. They will hear the "standard beat" but still
    be able to hear the sounds around them.

  5. David Harmon

    David Harmon Guest

    On Sun, 17 Feb 2008 14:59:21 -0800 (PST) in sci.electronics.basics,
    Does the user manual tell you anything about what kind of signal you
    get from that jack? Or, what do they normally suggest connecting to
    it? I guess a module sold as a "solid state relay" might do just
    what you want, depending on what that signal is.
  6. Somebody

    Somebody Guest

    Thanks chaps,

    Good suggestions. I should have mentioned that we've tried to use a
    strobe light before. The problem is twofold really. Firstly the
    comfort factor - it's a little disorientating having the room lit up
    so brightly, and secondly many of our pieces have parts which speed up
    which is why I wanted to use it with my metronome so I can control
    changes in tempo accurately.
  7. Somebody

    Somebody Guest

    The problem here is that there are 30+ of us all playing drums
    (surdo's, snares, repiniques etc). So an audio signal would be
    logistically very difficult given the amount of head phones cables and
    getting round our hearing protection. You're right about the sound
    versus light thing. It's much harder to feel the pulse visually, but
    many digital metronomes these days have a sound off function with
    LED's that flash in sequence. Sadly not bright enough. We often do, as
    you suggested, have one particular drummer who plays a very simple
    ostinato pattern and concentrates on keeping time, but as the majority
    of people in the group are amateurs (community project) it's not
    always very accurate. So I'm hoping that some kind of visual aid
    during rehersals will help to at least strengthen our abilites to spot
    the common places where we are likely to speed up or slow down.
  8. Somebody

    Somebody Guest

    Sadly I no longer have the user manual. But it's a simple headphone
    jack like on mp3 players walkmans etc. Can the type of signal vary? I
    know it's not a 'line out' because it has the headphone symbol just
    above the hole.
  9. Somebody

    Somebody Guest

    A friend of mine (an electrician not an electronics expert) suggested
    a PNP or NPN transistor. He used one when he was younger to make his
    fishing alarm louder using the original current from the alarm to
    switch on a much louder buzzer/battery circuit. Do you think this
    could be viable with the signal from a headphone socket? Tomorrow I'll
    see if I can get a measurement from a jack lead plugged into the
    metronome with his ammeter.
  10. Bob Monsen

    Bob Monsen Guest

    Can you build circuits? Here is what you will need:

    100k trimmer/potentiometer
    A plug input
    3 100k ohm resistors
    1 470 ohm resistor
    1 NPN transistor (2N2222 or 2N3904 will work. TO-92 case is fine)
    1 LMC555N timer chip
    1 0.1uF Capacitor
    1 High Brightness white LED
    1 5V regulated plug adapter (wall wart), or 3 AA batteries

    Connect them together like the following diagram:

    (view in monospace font, like courier)

    5V --o---------------------o--------o---------------------o--.
    | | | .---------------. | |
    | .-. | | | | .-.
    | | | .--)--o 1 GND Vcc 8 o--' | | 100k
    | 100k | | | | | | | |
    | Input '-' | | | | '-'
    |From Drum Machine o-----)--)--o 2 Trig Dis 7 o--. |
    .-. / \ ___ |/ | | | | | |
    100k | |<---(- +)--|___|--|NPN | | | | | |
    | | \_/ 100k |> .--)--)--o 3 OUT Thrs 6 o--o--o
    '-' | | | | | | |
    Sensitivity | | | | | | |
    | | | | '--o 4 Rst CV 5 | --- 0.1uF
    | | | | | | --- Capacitor
    | | | | '---------------' |
    | | | | LMC555N |
    | | | | |
    GND --o----------o----------o--)--o---------------------------'
    | |
    | V -> LED Out
    | -
    | ___ |
    (created by AACircuit v1.28.6 beta 04/19/05

    Plug in your drum machine, and adjust the sensitivity of the trimmer so that
    it lights up when the drum machine thumps.

    I have not built this circuit, but I simulated it using LTSpice, and it
    appears to work for inputs down to about 300mV.

    The LED will have about 9mA through it with the resistor shown. To go
    brighter, use a smaller resistor (down to about 220 ohms min)

    Note that the NPN transistor has the base connected to the input, the
    collector connected to the trig input, and the emitter connected to the
    ground. The package will generally say which leads are which, so you can
    connect them up properly.

    Have fun.

    Bob Monsen
  11. ehsjr

    ehsjr Guest

    Yes, absolutely - but you indicated that you have no
    knowlege of electronics so it's questionable if you can
    build the circuit to use the headphone output to
    flash a light (or lights). It seemed you needed an existing
    commercial solution.

    If you have sufficient interest and perseverence, you can
    learn to build a circuit that will do the job.

  12. Somebody

    Somebody Guest

    Blimey! Thanks Bob, that's fantastic. With a little help from a friend
    with a bit more electrical know-how, I think we may give this a go.

    Thanks again.

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