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Help Please. Answered

Help, I am Working on a projest, but for it to turn out well, I need to have the instructable that shows you how to hook an LED up to your speakers so when your spaker makes a sound, the LED lights up. Has anyone seen it/ can find it for me, Please?

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NachoMahma
NachoMahma

13 years ago

. Hmmmmm. I did a bit of searching and came up with zip. :( . I don't think hooking up just one LED will work. Since it conducts in only one direction, it's liable to mess with the sound. Just guessing. . I'd try putting two LEDs in parallel, with the polarity swapped on one of them. Run one side of the pair to a speaker terminal, the other to a potentiometer (others may be able to offer suggestions on ohm and watt ratings, I'd try a 100KOhm and 1/4W, but that may be too small), and from the pot to the other speaker terminal. Start with the pot at its' maximum value and slowly turn it down until the LEDs light up or the sound gets distorted.

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NachoMahma
NachoMahma

Reply 13 years ago

. BTW, most popular music today will not give you the effect that most, say, Classical music will. A lot of the music today is compressed so it sounds louder and you will get the most effect from material with a wide dynamic range (difference between the softest and loudest parts).

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Goodhart
Goodhart

Reply 13 years ago

I agree there. Back in that day, I got so tired of hearing the three cord "she loves you yeah yeah yeah" that I started to explore Classical. Lots of really neat works, and some variations on it too, like the Trans-Siberian Orchestra, etc. I haven't fooled around much in the acoustic arena, but would there be enough voltage to light the LED(s)?

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NachoMahma
NachoMahma

Reply 13 years ago

. Not sure. I used to know what kind of voltage to expect, but can't remember.
. How many volts would it take to push, say, 10W through an 8 Ohm speaker? P=Isquared * R, so if P=10 and R=8, then I=1.1. E=I*R, so E=8.8V. More than enough. Double-check my formulas and math, it's been a while.

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Goodhart
Goodhart

Reply 13 years ago

I haven't a clue. The math is not something I learned a lot of, being self-taught and more of a "let's see if THIS works" kind of guy at the time. I taught myself schematic reading by way of a book (and look back at it wishing I had someone back then to ask questions of, since it took me forever). I have a thought (maybe it should stay with me? :-) ), since we are speaking acoustics i.e. waveforms, will there be any reverse voltage of any significance to worry about. Wouldn't want it to exceed the breakdown voltage, or they would fail fairly quickly.

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NachoMahma
NachoMahma

Reply 13 years ago

> will there be any reverse voltage of any significance to worry about. Wouldn't want it to exceed the breakdown voltage, or they would fail fairly quickly. . Hmmmmmmmmmmmmmm. I forgot all about that. Between the two of us, we might have half a brain. :) I don't remember what kind of rev voltage a LED can take - and too lazy to look it up right now. "Regular" diodes are used in 12V wall warts, but I don't know how "regular" diodes compare to LEDs.

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Goodhart
Goodhart

Reply 13 years ago

"Regular" diodes are used in 12V wall warts, but I don't know how "regular" diodes compare to LEDs.

By "regular" I assume you mean "rectifier or bridge" diode?Diodes and types of diodes

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Bradley1000
Bradley1000

Reply 13 years ago

Ok guys. 6 3 volt LEDs. A speaker. HOW?

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NachoMahma
NachoMahma

Reply 13 years ago

. If my calculations are correct (big if), you should be able to just put the LED(s) across the speaker terminals, though this may bring the impedance below what is safe for your amp. If I had an LED handy, I'd try it with my stereo. Maybe I'll dig around in the junk box later. . Try using the plan I outlined above. If the sound gets distorted, abort. Might burn up a cheap LED or two, but so what? . If my scheme doesn't work, you will probably need a high impedance "sampler" (op-amp).

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Goodhart
Goodhart

Reply 13 years ago

Would a bipolar LED work "inline" ? Across would be nearly a short, wouldn't it ?

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NachoMahma
NachoMahma

Reply 13 years ago

. If you mean in series with the speaker, I'm pretty sure that will burn up the LED, but don't have enough experience with LEDs to know. I keep hoping that someone who knows what they are talking about will jump in. ;) . I have no idea what the resistance of a LED is - forward or reverse. That's why the warnings about impedance and shutting the amp down if distortion is encountered.

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Goodhart
Goodhart

Reply 13 years ago

Oh, If I could reclaim my "work space" (it has been confiscated for eBay future sales storage), I would fool around a little on the low end just to see what I could "light up" :-)

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NachoMahma
NachoMahma

Reply 13 years ago

. I'll rummage around for some LEDs and pots after a short nap. I have one on my RAID, but don't want to risk burning it up. My curiosity is aroused. . LEDs are expendable (except for the one on my RAID) and with a pot in the loop, I should be able to keep from damaging the amp (don't plan on pushing it that hard, anyway, may try it without a pot).

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NachoMahma
NachoMahma

Reply 13 years ago

. I found a couple of LEDs, but it seems that I've hidden my collection of pots from myself. Also found out I'm going to have to have some help moving the entertainment center - some of the wires are trapped between the cabinet and the wall. If it's not one thing, it's another.

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Bradley1000
Bradley1000

Reply 13 years ago

Can you please put that in a way an 11 year old can understand, Please? :3

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NachoMahma
NachoMahma

Reply 13 years ago

. Let's see.... . Get two LEDs, a 100K/0.25W potentiometer (variable resistor, volume control), and a few pieces of wire. Hook up the LEDs in parallel so that the + end on one LED is connected to the - end of the other. Connect one end of the LED pair to one of your speaker wires and the other end to the potentiometer - use wires as needed. If you connected the LEDs to the inside terminal on the pot, connect an outside terminal to the other speaker wire. With the pot terminals facing down and the adjustment shaft facing you, turn the shaft all the way away from your outside connection point (eg, if using the right hand terminal, turn the pot all the way to the left). Start playing some music and slowly adjust the pot until the LEDs start flashing. If the sound gets distorted, then my scheme is not working and you risk harming the amplifier, so stop and try something else.

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Patrick Pending
Patrick Pending

13 years ago

I have a circuit diagram ( 9 components) that uses: 2 capacitors, 2 Germanium diodes, 2 resistors, an LED and a transistor. Is that more complicated than you were expecting? Cheers, Pat. Pending

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theque
theque

13 years ago

would it be possible being that the speaker uses different levels of energy spikes to make the sounds it produces? this is just a guess, (ive got almost no experience)

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Brennn10
Brennn10

13 years ago

It is a pretty extensive schematic, and the one that I have the schematic for requires close to 30 components. In an overview, you would need a circuit that uses a microphone, two operational amplifier IC chips with some resistors, capacitors, and transistors.

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Bradley1000
Bradley1000

Reply 13 years ago

welll... It was more simple than that. It was mor like "cut your speaker wire open. Attach wire and LED. :/

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Brennn10
Brennn10

Reply 13 years ago

How is that possible without a microphone?

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Brennn10
Brennn10

13 years ago

How experienced are you with working with electrical circuits?