New speaker light project

Discussion in 'The Projects Forum' started by sensay, Dec 26, 2008.

  1. sensay

    Thread Starter New Member

    Dec 26, 2008
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    Hi everyone this is my first post thanks for having me!
    I have this project idea that im working on involving adding a cool electro luminescent wire design to a new speaker im building but the tricky part is i dont want to have any extra power cables running to the speaker. I want to find a way to power the light off of the speakers amplified signal. I was trying come up with a circuit that modifies and funnels the varying input frequencies into a single constant one without losses with an added capacitor unit to keep the 1w light temporarily running between songs, and also a simple diode unit at the beginning to prevent the speaker from seeing any changes. I am still new at this and would appreciate any help in the design of this circuit as i was incapable of coming up with one. thanks in advance you guys this is going to be a fun project and it will be fun to see what can come out of this.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    Running the electroluminescent wire with no loading on the amp is not practical. Are you after some effect other than just having it light up? Your circuit that " modifies and funnels the varying input frequencies into a single constant one without losses" does not seem to have the ability to do more than produce a constant level of illumination.
     
  3. sensay

    Thread Starter New Member

    Dec 26, 2008
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    thanks for the response, no im not looking for any effects im just trying to get it to work. Can you please explain what makes it impractical?
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
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    Pulling power off the amp output and charging a capacitor to run the electroluminescent wire is really more work than just using a wall transformer to do so.

    Any capacitor capable of supplying energy to the wire (voltage and current still a mystery) for periods of no/low music means that it has to be very large - perhaps also very expensive. Plus, during the 1/2 cycle when the diode is conducting, the speaker won't get much power, so the sound will be grossly distorted.
     
  5. sensay

    Thread Starter New Member

    Dec 26, 2008
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    i was hoping that due to the minuscule amount of energy required to power the wire that it would not be too difficult or expensive. were talking something on the order of 120v at 100MA. As for the the distortion and diode cutting out half the signal, should not be an issue. the circuit that powers the light is off to the side as a parallel setup not interfering with what the speaker sees.
     
  6. Audioguru

    New Member

    Dec 20, 2007
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    120V at 100mA is 12W on half the audio waveform.
    The circuit is in parallel with the speaker so it can take all the current and the speaker gets none for part of the sounds.
     
  7. beenthere

    Retired Moderator

    Apr 20, 2004
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    100 mills isn't too bad but not many audio amps ever put out anything like 120 volts. For an 8 ohm speaker, that would be 15 amps into it. Or 1800 watts into the speaker. Kinda loud. I've got a big old power amp that has 75 volts on the rails. Not ever enough to light the wire.

    By the way, 100 ma and 120 volts is still 12 watts. Not quite miniscule. I would use the supply that came with the elecroluminescent wire.
     
  8. sensay

    Thread Starter New Member

    Dec 26, 2008
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    i made a mistake here its 10MA, 100MA is on car 12v
     
  9. Audioguru

    New Member

    Dec 20, 2007
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    Your amplifier does not have an output of 120V, its output is variable but averages 12V when it is loud.
     
  10. sensay

    Thread Starter New Member

    Dec 26, 2008
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    i would use the inverter that comes with the wire but then i would have to step that 12v up to 120v. these are small technicalities that can be worked out. i still just dont have any ideas on how to approach that funneling circuit. the current powering the speaker will be varying from 30hz to 20khz but the inverter only operates at 60hz. Im sure a circuit could be devised that transforms the other frequencies into a single one. anyone could make a filter that only allows 60hz to pass though but that would waste the rest of the potential spectrum. every frequency varying pulse that enters this circuit must exit 60hz.
     
  11. SgtWookie

    Expert

    Jul 17, 2007
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    A resistor to limit current with a diode in series that charges a capacitor.
    You'll cause distortion and clipping, but hey - your light is a priority, right?

    Then you need an oscillator, like perhaps a 555 timer circuit. Unless you're really careful, that 60Hz will wind up being superimposed on the already distorted/clipped sound coming out of the speaker - but the light is the priority, right?

    Tell you what - just hook up a pink noise generator to the input of your amplifier, and crank up the volume. Disconnect the speaker, because you don't need it anymore; the light is the priority.

    Why don't you just move the speaker next to a wall outlet, and plug the inverter into the outlet?

    Your idea really is not practical. It will cause terrible sound distortion due to clipping of the music waveforms, and the light level will be very uneven.

    If you want to experiment with interesting lighting effects, you could build a "color organ" like was popular in the 70's. Those weren't powered from the amplifier either, but they took a high-impedance sample of the waveform and illuminated colored lamps (LEDs nowadays) depending upon the frequency spectrum of the sounds being played.

    But give up on the amplifier powered light idea. You'll likely wind up with one of three things:
    1) Mildly crappy audio, and really crappy lighting.
    2) Moderately crappy audio, and mediocre lighting.
    3) Really crappy audio, and mildly crappy lighting.
    You won't be happy with any of them, I promise.
     
  12. sensay

    Thread Starter New Member

    Dec 26, 2008
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    i thought only crystal oscillators could do an acceptable job at that task but only at frequencies i the Mhz.
    let me clarify what im proposing,
    the reason the speaker is not effected is because the diodes are on the line that goes to the lights only.
    [​IMG]
    instead of saying it wont work perhaps suggest ways in which it will.
     
  13. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    What is the power of the amplifier you want to use? On what average power do you use it?
    What are the specs of the "cool electro luminescent wire"?
     
  14. sensay

    Thread Starter New Member

    Dec 26, 2008
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  15. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    So I guess it is this: http://en.wikipedia.org/wiki/Electroluminescent_wire

    You can try this simple circuit and see how it works:

    It should be able to create fair steady low-power DC voltage. The first zener is there to protect the capacitor from overvoltage, the second one stabilizes to 12V. Diode bridge should be capable of sustaining 200V or more to be sure, in case you used more powerful amp.
    I designed for this: http://www.thatscoolwire.com/store/...SubCategoryID=142&GroupID=&SKU=WY-ELI-250-400 , but any othe low-power 12V thing should work.

    You may have to tweak the resistor values to find optimal vorking point for your loudeness, but be sure to use resistors with enough wattage, like 1 to 5W.
     
    Last edited: Dec 28, 2008
  16. sensay

    Thread Starter New Member

    Dec 26, 2008
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    thank you kubeek that diagram is very helpful, how do you think it will respond at low volumes? i will probably test on one of my cheaper amplifiers first.
     
  17. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    Let´s start with some numbers :)
    100W average into 8ohm speaker is cca 28Vrms. This would be in case of hardly limited signal at clipping. Under normal listening levels, you should assume cca one tenth of the voltage. This leaves us with cca 3V, with probable peaks to 7V on bass notes/drum beats. Another part of this is that there is a voltage drop on the bridge rectifier, cca 1.2V.

    So now as I see it now, you should use the 3V inverter, and a 3V zener diode, with cca 560ohm resistor instead of the 150ohm.
    You have to find the right values of the capacitor and resistors by trial and error, it depends on the loudness pretty much.

    You will also need to find the consumption of the inverter, to get you some starting point to see what power it needs, and then you can see better what values you need.
     
  18. sensay

    Thread Starter New Member

    Dec 26, 2008
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    yea it would probably be much better to stick with that 3v inverter like you said as using the speakers at full volume will be a rarity. i wonder how the inverter and wire will handle the 12v spikes...
     
  19. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    That is why there is a big capacitor and a zener in the circuit, to make the output voltage to the inverter stable.
     
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