servo help

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scarecrow
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servo help

Post by scarecrow » Sat Jan 12, 2008 8:55 pm

where can i buy a controller that will move a servo to the singers voice
and not to the music when hooked up to a cd player?

Droidwerkz
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Post by Droidwerkz » Sat Jan 12, 2008 10:53 pm

it isn't that simple

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jaem
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Post by jaem » Sun Jan 13, 2008 4:44 pm

An audio signal coming from a CD player is just a single signal; you could potentially make something like that by triggering on the vocal frequencies, by filtering out other ones like you would with an equalizer - even better with a DSP - but as Droidwerkz said, it's not simple.

If you wanted something like a mechanical VU Meter, that would be simpler, but still not that easy to control a servo. The other issue is that servos (at least your standard hobby RC servos) are pretty slow - I doubt you could find one that could keep up with the music easily, if at all. (correct me if I'm wrong, people)

If you're serious about this, you might want to look into what they use to control motors in laser show machines (the name escapes me), but again, that's getting pretty complicated, and I will leave any elaboration on that topic to people who know more about it than I.

EDIT: I didn't read your post properly the first time. As to where you could buy such a thing, it would depend greatly on your purpose. If you want a generic machine that can move a servo for whatever you need to do - good luck; music-controlled lighting and effects machines are common (albeit expensive), but you'll have to give us more information to help you. What is the end purpose of this device? How much are you willing to spend? What are you trying to integrate this into, and what is your level of skill?

Droidwerkz
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Post by Droidwerkz » Fri Jan 25, 2008 4:09 am

really what has to be done is to program a microcontroller to run a predefined set of instructions which turn a motor or activate a solenoid to run compressed air through a piston to activate the mouth. you would then have to either use an instruction from the microcontroller to start the cd player or if you use a pc, start a wav file or the pc cd rom. the reprogrammed movements would match the lyrics as well as you program them to.

Bigglez
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Post by Bigglez » Fri Jan 25, 2008 6:15 pm

jaem wrote:If you're serious about this, you might want to look into what they use to control motors in laser show machines (the name escapes me), but again, that's getting pretty complicated, and I will leave any elaboration on that topic to people who know more about it than I.
Greetings jaem,
Perhaps you are thinking of a Mirror Galvanometer?
Typically these deflect the laser beam using a mirror.

Other technology to deflect a light beam include holographic
mirrors and prisms. These are all mechanical and good for
low to audio frequencies.

To go faster the laser can be deflected by a Bragg Cell,
which uses acoustic standing waves in a quartz block to
deflect the laser beam.

Comments Welcome!

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