# Looking for a simple circuit for a "reverse" color organ



## GOT (Apr 17, 2007)

I basically want a lamp (can be AC or DC) to dim in response to the volume of a recorded sound. That is, the light is on normally, but dims when a recorded sound is played. I am not looking for a on/off system with some threashold volume. I need it to dim slightly to soft noise and more to louder noises. Can anyone help?


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## Dr Morbius (Sep 21, 2004)

why would you need this?


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## MansionHaunter (Sep 20, 2006)

Depending upon the lamp you use (and the power supply it requires), the circuit can be either very simple or somewhat complex. 

How bright does the light have to be, and what is it illuminating?


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## GOT (Apr 17, 2007)

I want the lights to dim when my ghosts pass screaming through the room. The light does not have to be bright. A flashlight bulb would suffice.


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## jrzmac (Aug 22, 2006)

i think this is what you're talking about: http://www.hauntmasterproducts.com/14.html . i want to do the same thing, but 70. is a bit steep for me.


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## Stratusfear02 (Oct 1, 2006)

Very cool concept. From watching any show on paranormal activity we know that "they" draw energy to manifest. therefore the dimming/flickerng of lights is one neat idea. I'll have to do some research on this one


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## jrzmac (Aug 22, 2006)

basically i want the lights indide the house to flicker, when the flood lights flash outside from the tnl machine. sound simple enough, but.... i tried hooking up the tnl machine to a flip flop control thing i built, it actually worked, as the lights would stay lit and flicker off when the thunder sounded, but the damn relay was buzzing like a son of a b...


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## gmacted (Jan 18, 2006)

jrzmac said:


> basically i want the lights indide the house to flicker, when the flood lights flash outside from the tnl machine. sound simple enough, but.... i tried hooking up the tnl machine to a flip flop control thing i built, it actually worked, as the lights would stay lit and flicker off when the thunder sounded, but the damn relay was buzzing like a son of a b...


I wouldn't use a relay in this application unless it was a "solid state" relay. Most relays are mechanical in nature and will "wear out" with use. Data sheets will usually specify the "mechanical life" of a relay which will give you a good idea of how long they will last. The typical mechanical life of a relay is usually 1 - 10 million operations. This may sound like a lot, and for most applications it probably is, but in this case the "buzzing" is cycling through a lot of operations. It may last for a while, but you will eventaully need to replace it. A "solid state" relay is not mechanical and will last much much longer. The only problem is, they are usually somewhat expensive.


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## MansionHaunter (Sep 20, 2006)

This might work. I haven't tried it, but if my calculations are correct the values shown should work.

This is a very simple two-transistor circuit that will take the speaker-level audio output of some source like a stereo, radio, tape player or whatever and then dim the lights whenever the audio input increases. They should be full on all the time, until sound is played, when they should dim in accordance with the input level. The variable resistor is a level adjust to make it work with different output levels.

The light bulbs designed in are 5 to 10 watts each, and 12 V. This would assume you'd run it off of some 12V source capable of putting out at least 3 Amps.


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## GOT (Apr 17, 2007)

Thanks! I will try it out right away and let you know if it works.


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## GOT (Apr 17, 2007)

Sorry, I am new to electronics. What is the 22uF component represented with the two straight lines and the + sign?


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## Otaku (Dec 3, 2004)

That would be a 22 microfarad electrolytic capacitor. When wiring this type of cap, be sure to keep the polarity correct as shown in the drawing. They tend to explode if polarity is reversed. Neat circuit, MansionHaunter - I'll have to try this one out, too!


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## MansionHaunter (Sep 20, 2006)

Sorry about not labelling things better; the .1 uf is a ceramic capacitor, and the 22uf is an electrolytic. Everything should be available from Radio Shack.

One component change, though: the 2.4K resistor on the base of the 2n3904 to ground should instead be 6.8K, otherwise the incoming audio will not cause much change; the lights will rarely ever dim. On the transistors, the base lead is the one coming out to the left. The emitter is on the bottom right, with the arrow, and the collector is on the top right.

I'd try this on a solderless breadboard first before committing it to a prototype circuitboard using solder.

I might try it myself this weekend to get the values exactly right.


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## GOT (Apr 17, 2007)

I have a 12V transformer that puts out 1 amp. Is that good enough or should I buy a different one?


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## MansionHaunter (Sep 20, 2006)

1 Amp isn't enough to do much serious lighting; it'll light up a single 12v bulb to a decent degree, but for something that's going to be effective enough to fill a room with light you'll need more than that.

I'd suggest at least 3 Amps or better.


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## GOT (Apr 17, 2007)

This will be a very small room (9' x 8') and I want it dim. I think one flashlight bulb would do, assuming it was brightly lit. Would the rest of the circuit work at 1 amp or would other adjustments need to be made? I am just trying to avoid additional cost here as well as I am not comfortable wiring up those transformers I saw at Radio Shack.


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## heresjohnny (Feb 15, 2006)

MansionHaunter, this looks like a cool circuit. I may try to breadboard it this weekend if I can find the time and get the monster mud off my hands.

GOT, I also like to keep things dim, and I think you already have your answer from a previous post by MansionHaunter (1 Amp isn't enough to do much serious lighting; it'll light up a single 12v bulb to a decent degree), but I'll leave it to MansionHaunter to verify that  .


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## MansionHaunter (Sep 20, 2006)

1 Amp will work for dim light, and the circuit should work as shown, although I'll make the adjustment in the power input to see whether the values should change.

By the way - if you're starting with a 12V transformer, you'll need to rectify and smooth out the output to make it DC so the circuit will work at all.










The above circuit should do the trick.


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## MansionHaunter (Sep 20, 2006)

whoops... my bad... I got the bridge hooked up backwards. Just a sec... that's better.
Radio Shack has an integrated bridge rectifier that will do the trick here.


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## GOT (Apr 17, 2007)

Anyone breadboard this yet?


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## Moon Dog (Oct 3, 2006)




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## Adam I (Jun 16, 2007)

Does anybody have a copy of the circuit?
The lmage is gone.


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## screaminscott (Oct 13, 2006)

*simple solution*










You can use one of these screw-in adaptors, intended to turn on a light at dusk. THese are cheap, and will make the light turn on slowly, not on/off.

Then take a regular light organ circuit, and place the light in front of the sensor. You can mask it in an enclosure both to sheild the sensor from ambient light and to hide the light.

When the color organ turns on the light in front of the sensor, the light in the screw-in adaptor will dim.

I may seem convoluted, but the advantage is that you don't need to wire a reverse-color organ circuit.


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## heresjohnny (Feb 15, 2006)

Just looked at this thread, I can't tell if you have a solution yet or not. First, here is a circuit I found a while back, uses a photosensor to turn on a relay once it gets dark enough. http://www.zen22142.zen.co.uk/Circuits/Switching/darksw.htm. I have never built it.

I have learned a bunch about op amps and color organs lately, and I think you can take this color organ circuit http://www.scary-terry.com/audiodriver/audiodriver.htm, flip the inverting and non-inverting inputs on the second op-amp (the comparator), and you will end up with a color organ that turns off in response to sound. I will try this out tonight. If this works, this could drive a battery operated prop through a transistor like a TIP122, or it could use a relay to trigger an AC powered prop.


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## heresjohnny (Feb 15, 2006)

OK, so its not as simple as swapping the inputs. Let me play with it some more.


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## Ironman (Feb 4, 2006)

I'm anxious to see how this turns out when you get it nailed down.


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## heresjohnny (Feb 15, 2006)

Ironman said:


> I'm anxious to see how this turns out when you get it nailed down.


Will do. I have the single talking skull circuit nailed, and am finishing the prototype board for that. The reverse color organ will be next.


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## gadget-evilusions (Jan 26, 2007)

I just had a new board designed for me that operates at as a standard color organ type light controller, but also will turn out the lights on a second channel. When an adjustable thresehold is reached the second channel will shut of and slowly fade back on, simulating what your house lights would do in a black/brown out situation from lightning strikes. I just haven't got the contoller up on our website. I will have some of them at MHC.


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