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http://www.instructables.com/id/Dancing-lights/ Home Sign Up! Explore Community Submit All Art Craft Food Games Green Home Kids Life Music Offbeat Outdoors Pets Ride Science Sports Tech Dancing lights by neelandan on May 29, 2007 Table of Contents intro: Dancing lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 step 1: Take the lamp apart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 step 2: Three button cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 step 3: And an LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 step 4: Battery holder, LED and switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 step 5: The switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 step 6: Connect wires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 step 7: Making connections: strip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 step 8: Making connections: Twist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 step 9: Making connections: join . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 step 10: Transistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 step 11: LED to Collector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 step 12: Battery negative to emitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 step 13: The wet finger test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 step 14: Connect to emitter and base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 step 15: Connect a resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 step 16: Earphone jack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 step 17: Cut ends and strip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 step 18: The project is complete. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Related Instructables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Advertisements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Customized Instructable T-shirts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Dancing Lights

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Page 1: Dancing Lights

http://www.instructables.com/id/Dancing-lights/

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Dancing lightsby neelandan on May 29, 2007

Table of Contents

intro:   Dancing lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

step 1:   Take the lamp apart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

step 2:   Three button cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

step 3:   And an LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

step 4:   Battery holder, LED and switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

step 5:   The switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

step 6:   Connect wires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

step 7:   Making connections: strip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

step 8:   Making connections: Twist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

step 9:   Making connections: join . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

step 10:   Transistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

step 11:   LED to Collector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

step 12:   Battery negative to emitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

step 13:   The wet finger test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

step 14:   Connect to emitter and base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

step 15:   Connect a resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

step 16:   Earphone jack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

step 17:   Cut ends and strip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

step 18:   The project is complete. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Related Instructables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Advertisements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Customized Instructable T-shirts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

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intro:  Dancing lightsIn response to music. Use a LED light removed from a pen, lighter or similiar device and a few other components to build it. No soldering involved. This is a simplifiedversion of the blinking LEDs instructable posted here earlier. I shall try to elaborately describe each step so that a person with little experience can successfully build one.

The emphasis shall be on the methods of wiring and testing a simple circuit. The product of this instructable is not the blinking light you build - it is the knowledge that yougain as you build this extremely simple circuit, with materials that are commonly available, with simple tools and very little specialised skills.

Image Notes1. These two LEDs light up on the peaks of the music.

step 1: Take the lamp apartParts: Now that many gadgets come with an LED torch (flashlight) built in, it's easy to just buy one and take apart for the batteries and LED. You have to liberate the torchpart from the pen, cigarette lighter or keychain or whatever. You should get three button cells, one LED and some sort of switch for completing the circuit.

The picture shows a pen with built in LED flashlight.

step 2: Three button cellsThe LED torch (flashlight) consists of three button cells and an LED.

The three button cells are visible in this picture.

Image Notes1. Button cells

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step 3: And an LEDThe LED is inside the white plastic sleeve in this picture.

Image Notes1. The three button cells, connected in series. They make a battery of about 4.5 volts.

step 4: Battery holder, LED and switchThese three components form a module. The switch is a springy piece of metal which makes contact with one leg of the LED when the button is pressed.

Image Notes1. The three button cells, connected in series. They make a battery of about 4.5 volts.

step 5: The switchHere is a closeup shot of that switch.

The second picture is that of a similiar module removed from an empty cigarette lighter tossed in my path by an unknown benevolent wellwisher. Many thanks to thatmagnanimous person.

Image Notes1. The switch

step 6: Connect wiresConnect two wires across that switch. The movie shows how you can test it.

The idea is that you connect an electronic switch to these wires and connect the music to it so that it closes in time with the beat of the music.

Then you will have a white lamp which flashes in time to music.

Page 4: Dancing Lights

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step 7: Making connections: stripYou have to know how you can reliably connect components together using wire. This is an essential skill you need to acquire.

First, strip the insulation off the end of the wire. Cut the covering without nicking the wires inside. This takes some practice, and the best method I have found useful is toscribe a line around the insulation with a very sharp blade. The end can then be pulled off.

Trying to cut entirely through the insulation usually scratches the wires inside as well, leaving them fragile. Subsequent operations will cause the wires to break at thispoint, and you will have to do the stripping again. Leave plenty of slack in the wires in your early projects in order to allow for this sort of thing.

step 8: Making connections: TwistIf you are using stranded wire, ie, wire that consists of a number of small wires bunched together inside a plastic covering, the previous operation will have you looking atsomething that looks like the business end of a witch's broom about to take off into the blue yonder.

So twist them. Hold the frayed end between thumb and forefinger of one hand, and rotate the (larger) part of the wire with the other hand, and the strands will wrapthemselves around themselves and present a very nice and respectable appearance, as in the picture.

step 9: Making connections: joinWrap the wire around the lead of the LED to make a neat joint. If you look at that picture again, one wire has been wrapped around the free lead of the LED, and theother wire has been jammed into the battery holder against the piece of metal serving as one pole of the switch.

I did that by pulling that metal piece out, and reinserting it with the wire wrapped around it.

Now when you touch the free ends of those wires together, the LED should light.

Next, we shall command a demon to sit there and touch the wires together in time to music.

Off we go, to get such a demon.

Page 5: Dancing Lights

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step 10: TransistorsHere be Demons. A whole bunch of them.

This is a selection from my collection of transistors. Some of them might even be undamaged and work as new.

We shall use a transistor to switch on the LED according to the music. You can find transistors inside virtually every electronic gadget. Try to scrounge some really oldgadgets because the transistors inside modern ones are likely to be too small to be seen without a microscope.

I shall use the BD135 from the collection in the picture. It is said to be a medium power silicon NPN transistor.

If you have to buy one, get the BD135 or an equivalent. Or try any transistor you pull off some electronic gadget. It has to be NPN, otherwise the type, make, size etcdoes not matter much.

step 11: LED to CollectorTransistors have three terminals called the collector, emitter and base. These names originated long ago from the age when transistors were two sharp points pressedinto a block of germanium.

For the BD135, the center lead is the collector. The other two are the base and collector, obviously. But I get confused, and have to refer to the datasheet to get thecorrect info.

If you are using the BD135 the pins are labelled in the picture. If you are using some other device try searching for the data on the web (use google).

The wire from the LED has to connect to the collector of the transistor, and is here shown stripped in readiness for connecting.

Page 6: Dancing Lights

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step 12: Battery negative to emitterThe small exposed face of the button cell is its negative terminal. It has to be connected to the emitter terminal of the transistor. That wire has been shown stripped priorto connecting it.

step 13: The wet finger testWhen the collector and emitter of the transistor are connected in place of the switch, it can control the lighting of the LED. A small current into the base (the free terminalof the transistor in the picture) will cause a much larger current to flow through its collector, both currents sharing the emitter lead.

When the transistor has been connected up as in the picture, the LED must remain off. At least it should, if the transistor is not faulty and it has been connected the rightway around.

Now bridging the collector and base leads of the transistor will cause the LED to light. This is the classic Wet Finger Test.

Watch the video. I am holding the battery positive (one lead of the LED) in one hand, and touching the base of the transistor with the other. When the base lead hits thewet part of my finger, the LED lights up.

Page 7: Dancing Lights

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step 14: Connect to emitter and baseIf you have successfully applied the wet finger test, the next step would be the conncections to apply the music signal.

The transistor will conduct, causing the LED to light, whenever the voltage on its base is more than about half a volt (500 millivolts) with respect to its emitter. We applythe music signal between the base and emitter of this transistor, so that the LED will light in sympathy with the music.

The picture shows two wires connected to the base and emitter of the transistor.

When you have finished this step, the base and collector will have one wire each wrapped around them. In complete contrast, the emitter lead will have two wireswrapped around it.

step 15: Connect a resistorNext, we need a resistor. Anything between 47 ohms and 1,000 ohms will do, it is not that critical. A 470 ohm resistor was what I used, as shown in the picture.

If you open up an old portable radio most likely you will get a collection of them. Try a few, any one of them might work.

Depending upon the source of your audio (music) signal, this resistor might not even be required.

Page 8: Dancing Lights

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step 16: Earphone jackNext, we need to have something that plugs into a music signal source. The plug end of a pair of stereo headphones will do. Get the plug off a pair of broken oldheadphones or earphones if you cannot find the plug by itself.

Page 9: Dancing Lights

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step 17: Cut ends and stripYou need to get the signal off the plug. Cut the wires somewhere and strip them. This earphone lead from a pair of really cheap earphones had bare copper braid and anenamelled wire inside the plastic insulation.

If you get such a lead, scrape off the enamel with a sharp blade - use gentle pressure to avoid nicking the wire.

step 18: The project is complete.Connect it up, and the project is complete. Here in the picture, I have used a length of wire between the circuit and the earphone lead, but that was just for convenience.

Insert the plug into your tape player, MP3 player or computer sound card and try playing some music. The LED will light up in time to music.

But then there is a problem - you can see the LED light, but you cannot hear the music play. Some powered speakers have a socket for the other speaker, and you mighttry plugging this into that.

The video shows my test of my prototype.

Related Instructables

Page 10: Dancing Lights

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Comments42 comments Add Comment

 deadfire55 says:  Feb 16, 2009. 2:22 PM  REPLYIf anyone wants another link that explains the wiring more.If anyone wants another link that explains the wiring more.

 Taotaoba says:  Jun 5, 2007. 9:32 AM  REPLYYou got a lot of old stuff. Nice instructable! Thanks. If you could put a schematic draft, that would be even better.

 neelandan says:  Jun 6, 2007. 3:37 AM  REPLY.

 joinaqd says:  Feb 2, 2009. 8:22 AM  REPLYwhere in the world did you get all those transistors?!?!?!?

 joinaqd says:  Jan 28, 2009. 5:55 PM  REPLYawesome job dude...i tried the flashing lights thingy with my iPod and the lights worked!!!

 joinaqd says:  Jan 25, 2009. 5:34 PM  REPLYhmmmm...you think the transistor might be able to amplify sound also?like from an iPod to a Speaker?

 Trust_in_Dust says:  Jun 8, 2007. 5:44 AM  REPLYnice schematic! i love the hand drawn ones... so scrappy.

 awkrin says:  May 7, 2008. 5:44 AM  REPLYme too, but only those drawn by hand and scanned or drawn on computer, but with a kind of anti alias, like blur...

 Taotaoba says:  Jun 6, 2007. 6:48 AM  REPLYGreat! Thanks.

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 cupnoodles2 says:  Jan 29, 2009. 8:57 PM  REPLYoh i didnt used a resistor does that matters?

 Eirinn says:  Feb 2, 2009. 8:20 AM  REPLYDepends on the LED voltage requirement, if you send through 4.5v to a 3v LED it will burn out relatively fast compared to if the voltage was regulatedthrough a resistor.

 cupnoodles2 says:  Jan 29, 2009. 8:57 PM  REPLYHey man thats sweet but my led doesnt go too brighty i dunno y does i need an amp to make it verry bright?

 kemical79 says:  Jan 14, 2009. 1:51 PM  REPLYVery exaustive explanation....but...any idea about how it works? ; )http://www.youtube.com/watch?v=cQaF4bmuojo

 J_Mi says:  Oct 21, 2008. 2:49 AM  REPLYQuestion, Could you just use a simple relay instead of all this crap? :)

 junits15 says:  Jan 3, 2009. 8:36 AM  REPLYthe transistor is bascily the same as a relay, just smaller and quieter.

 J_Mi says:  Jan 6, 2009. 1:53 PM  REPLYOh.. I knew that.

 junits15 says:  Jan 3, 2009. 8:53 AM  REPLYwhen I saw you picture with the transistor in it, I noticed that it is an amplifing transistor, that is great for this project because it is way more sensitive tovoltage over the collector.

 =SMART= says:  Sep 5, 2008. 3:07 PM  REPLYLOL did you use a scanner to get those pics ?!!?Awesome !

 slimguy379 says:  Jul 7, 2008. 7:22 PM  REPLYyour avi file didn't work for me (I'm using quicktime)

 neelandan says:  Jul 8, 2008. 12:16 AM  REPLYYou aren't missing much. The movie just shows the blinking LEDs and has some music.

Next time, I am going to put the movie up on www.blip.tv

 Nunavutnewsrules says:  Jun 26, 2008. 2:24 PM  REPLYHey nice job. I am gonna make this but i am not gonna use the resister do i just replace it with a wire?

 neelandan says:  Jul 8, 2008. 12:05 AM  REPLYJust leave it out, it might work.

If it doesn't, you can try leaving the earphone in circuit (in place of the resistor).

 awkrin says:  May 7, 2008. 5:18 AM  REPLYnice idea, but I was very impressed with the high quality, really close pics

 urbosssez says:  Mar 4, 2008. 8:16 PM  REPLYw00t mines works!but my transistor sucksso it only works well with my rbg ledsbut atleast it works!thanks A TON for this instructablevery clear and simple!

Page 12: Dancing Lights

http://www.instructables.com/id/Dancing-lights/

 worleyll says:  Feb 24, 2008. 7:18 AM  REPLYIf you have a large stereo you can just hook the lights straight up to the speaker wires.

 Zujus says:  Feb 5, 2008. 12:51 PM  REPLYAwesome! Simple and nice for starters ;)

 bignothing says:  Jan 20, 2008. 10:22 AM  REPLYAny idea on how many of these I could wire to an amplified signal before the effect lessens noticeably? Or would it make more sense to wire multiple leds toone transistor, and then fiddle with the resistor? I'm trying to figure out the simplest way to have 4-6 sound-blinky leds on the front of my guitar amp.

 Joe426 says:  Nov 15, 2007. 4:24 PM  REPLYAwesome, i did this and it worked great! - i used a TIP31 NPN Transistor - Radio Shack.

 Hawaii00000 says:  Nov 2, 2007. 11:04 PM  REPLYMaybe i could use a mic to make it more portable.

 neelandan says:  Nov 4, 2007. 9:51 PM  REPLYNo.

The signal from a mic is not large enough.

 Hawaii00000 says:  Nov 6, 2007. 4:11 PM  REPLYI know but if it were attached to somthing like this.........

http://www.amazon.com/SPY-EAR/dp/B0006GKFZ8 (Its a little toy that is supposed to amplify sounds amd uses a headphone jack)

 Hawaii00000 says:  Nov 3, 2007. 6:40 PM  REPLYI f you don't know how many ohms your resistor is go to http://www.the12volt.com/resistors/resistors.asp

 Hawaii00000 says:  Nov 2, 2007. 7:42 PM  REPLYI can't describe how much this helped me!!!!!!!!!!! I have been wanting to do this for soooooooooooooooooooooooooooo long. Very easy to follow.

All in all A great instructable!!

 Neodudeman says:  Sep 5, 2007. 12:46 AM  REPLYThis is super nice. I like it a lot. It's much simpler than the circuit I found:

How loud must the input be? I'd like to make one that's connected right to a microphone on a lapel.

 neelandan says:  Sep 5, 2007. 2:24 AM  REPLYThe input has to be loud enough to be heard in a speaker or headphone. It cannot work directly from a microphone.

The stages of amplification needed to light an LED in response to the sound picked up by a mic would make that a very complicated project, and Igenerally tend to lose interest and give up half to a quarter of the way through such giant projects.

I do not have a digital camera, so I use the scanner to take pictures. The circuit is arranged on the scanner's glass plate, and a piece of clean whitepaper placed over for the background.

Generally scanning at 400 to 600 dpi and then reducing the size gives the best results.

Page 13: Dancing Lights

http://www.instructables.com/id/Dancing-lights/

 Neodudeman says:  Sep 7, 2007. 1:39 PM  REPLYneelandan, you're so amazing.

 Neodudeman says:  Sep 5, 2007. 12:48 AM  REPLYI also like the way you took pictures of the bits and pieces. How'd you give it such a clean look?

 Hegpetz says:  Jun 16, 2007. 11:00 AM  REPLYI'm very amateur in electronics, but to solve the no sound issue - couldn't you take an input and wire that parallel to the transistor? That way the input signalgets split in duplicates, and then you can plug your normal speakers into the input you just made, and the other path would drive the LED?

I'm sure something about that is flawed though, but hey, it's a start? :)

 gandalfsz says:  Jun 12, 2007. 2:22 AM  REPLY.

 therian says:  Jun 5, 2007. 11:16 PM  REPLYwhy you dont put blocking capacitor?

 Ohm says:  Jun 5, 2007. 6:17 PM  REPLYmight be use full in a auto wah circuit or other envelope filter.

 T3h_Muffinator says:  Jun 5, 2007. 4:40 PM  REPLYDude, I've been trying to do this for ages with my USB Christmas Tree, but all of my transistors kept blowing. I guess I should look up the data sheets beforeblowing them.

By the way, "MAD PROPS" for using HD cables as wiring. If you check out my Beating Heart T-shirt instructable, you'll see they're my favorite =)