Help finding correct component

Discussion in 'The Projects Forum' started by Cbas, Oct 31, 2012.

  1. Cbas

    Thread Starter New Member

    Oct 31, 2012
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    Hi, I am doing a project in which I am sending signals from an Arduino to an array of speakers and need a component which could act as a voltage threshold gate - so that it only lets a signal pass on to the next speaker in the array if the signal it receives is over a certain threshold.

    Is there some kind of operation chip out there that I could use for this purpose? I have been searching all over but cannot find anything that fits my project. I want there to be a lot of speakers in the array, each with their own threshold chip, so it would be best if the solution was inexpensive.
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Can you not convert the audio to dc, then use an op amp comparator like a LM3914 VU meter, to swtich on a set of fets. or opto couplers?
     
  3. wayneh

    Expert

    Sep 9, 2010
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    I don't understand what you're doing exactly, but a zener diode does more-or-less what you've described. No current flows through it unless the voltage rises above a threshold. But if you then want large currents to flow, you'll need a high current zener and I'm not sure that's practical.
     
  4. Cbas

    Thread Starter New Member

    Oct 31, 2012
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    Thanks for the suggestions, I couldn't find much useful information about the LM3914 VU meter, but zener diodes look like the way to go.

    If I keep the circuit running at a low voltage, could these zener diodes as gates? (ei. receive a signal and not pass it on)
     
  5. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    I think that will sound terrible. Can you go back to the original design concept and say WHY you need to have an array of speakers and why they need to activate sequentially as the sound level rises?
     
  6. Audioguru

    New Member

    Dec 20, 2007
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    Each speaker needs its own audio power amplifier. Then an audio multiplexer circuit feeds the inputs of the amplifiers.
     
  7. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    If you replace the leds with opto couplers, then as the level increases each opto will turn on one by one, use the opto to switch your speakers on .
    http://www.google.co.uk/imgres?imgu...qUULbpAa6Z0QXr6YHADQ&ved=0CCUQ9QEwAg&dur=1371
     
  8. wayneh

    Expert

    Sep 9, 2010
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    Sweet solution, Dodgydave. Elegant. But it wouldn't send to the incremental amp just the incremental part of the signal, right? It would send the same large signal to all "on" amps and thus give a non-linear response.

    I think RB's point is valid. What is the point of this approach, as opposed to having all the amps on all the time? No signal means the amps are quiet. Big signal, they get loud. Is this a power saving scheme?

    Also do you not care what frequency is making up the signal? My sub turns itself on if there's enough of a signal in its range, but it's not reacting in real time. I mean it comes on and stays on unless no additional content comes along over the span of a few minutes.
     
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