LED Music Sync Lamp!

Step 2 Circuit Diagram

+6V ................. LEDs +ve

LEDs -ve ...............150 variable resistor .....................LM 340 5v regulator (1st pin)

LM 340 5v regulator (3rd pin)................Transistor (1st pin)

Transistor (3rd pin) ....................... -=Ground=- ...................audio signal

---

transistor (2nd pin) other audio signal

Comments

[june1234]

Wat does it mean by Nokia charger Amplifier? can i find other substition for it? care to give examples?

[Chu Guk]

He just means a cell phone charger. You just cut the end off and strip the wires, use them as a voltage transformer.

[kacper00100]

Ok, so I want to do this but I have a 12V LED strip thing and I have a few questions:

1. Do you really need a voltage regulator?
2. If you dont can I use this transistor: BC547C

[joshr45]

ok so ive gotten partially done with this i have the LED Blinking very dimly to music i dont believe the Variable Resistor i have is working at all doesnt seem to matter one way or another, so basically without a power supply im running the 1 LED light off of the speaker, its just night time and i cant turn it up to see if it will work with my car system, the crap speakers i have put out 5v abouts, BUT the odd thing is i have a phone charger on the other end where the + and - go and its unplugged yet the light blinks, if i plug the phone charger in the wall the light is constant on.

[double_d_mfl]

try flipping the transistor around, the middle pin is the audio input, but switch the two other pins connections. i had the same problem, but once i flipped it around, good to go :)

[tysonscott2002]

Can someone draw up a working schematic for this? i am having no luck with a power supply above 3 volts, and no luck at all adding a transistor or regulator.

[djpain]

What if i but this NPN which is 160VOLTS
http://cgi.ebay.com/20-pcs-2N5551-Transistor-NPN-160-Volts-600-mA-TO-92_W0QQitemZ250382441185QQihZ015QQcategoryZ4666QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

And this voltage regulator???

http://cgi.ebay.com/79L12-12V-0-1A-Negative-Voltage-Regulator-TO92-ST-10pcs_W0QQitemZ220364966454QQihZ012QQcategoryZ117000QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

THNX FOR HELP!!

[diyman]

is a very cool project, I am thinking of doing this but with 100 LED's. What wud I have 2 change to get this to work like your with 40 LED's. Also I have a cheapo speaker for my PC http://www.google.com/products/catalog?hl=en&q=speaker&oe=UTF-8&cid=11295985947209587805&sa=title#ps-sellers. How would I go about connecting the wires from the transistor to the speaker. does the speaker have a built in amp?

BTW I am a complete noob in this kinda stuff.
Thanks
diyman

[godfreyandthandi]

your speaker will have a built in amp, split the signal so half goes to the transistor and half to the speaker.

[diyman]

so let me get this clear. so lets say i hook up a pc to m speakers via a 3.5mm audio cable. then connect the 2 wire coming out of the transistor to the "audio cable???" is that right, i'm confused now. wud u mind drawing a rough figure for me. just cannot picture it. Thanks

[kjk53913]

okay, so im a begginer with this kinda stuff...i have a home theatre system in my room. i have used the speaker outputs to flash like 10 or 15 LEDs at a time with the bass to songs. but its controlled by the volume so for more lights it has to be pretty loud for anything to light up....i was wondering if it would be possible to, say, connect a string of old christmas lights or a set of rope lights to a wall outlet & use the power from the theatre system speaker outlets as a switch to turn the string on and off...jus an idea lol

[junits15]

make this circut so it controls another NPN that controls the string of lights (this is only for low voltage 3-5V)

[thegeeke]

If you just want your lights to turn on and off with your amp. there should be a swithched outlet in back. If you want to sync. them you have to 1. Get a "junk" set. 2. Take the plug off the wire. 3. Strip the wire and put the positive in the red speaker output, and put the neg. in the black output. (MAKE SURE YOUR AMP IS UN-PLUGED WHEN YOU DO THIS) (I learned the hard way)

[optimized4perfection]

yes thats more or less the same idea and this should work once you get the power and the resistors correct. most of the wall power adapters that i have are at most slightly over 1W, which might not be enough for christmas lights. just have something to convert enough power and vary the resistances unitl you get the desired effect. also, leds respond to the change in voltage differently than other lights.

[nyxynyx]

Although my setup is working, the leds are not very bright. Using a multimeter, the voltage drop across the leds are less than 1v. However, the potential difference between the led and the middle pin of the npn transistor is 5v. Am i doing something wrong?

[optimized4perfection]

try without the voltage regulator. i have remade it without the voltage regulator and it works too try a stronger amplifier signal. i dont think this can be measured easily with a multimeter or the voltage of the leds when it is runnning off an audio signal for the variable resistor portion, use ~100ohm resistors in parallel to reduce resistance instead.of one variable resistor works for me since i cant find a good variable resistor

[nyxynyx]

i tried without the voltage regulator and its slightly brighter. The audio ouput from my computer is already max. When i switced to a 12V source, the LEDs are at full brightness but stays on all the time. I used 20ohm resistors and it is still not bright. I tried using a darlington pair to boost the current but its still the same. Is it the transistor that im using? What is the part number of the NPN transistor u used? What should i try next?

[optimized4perfection]

first try to get the leds maximum brightness correct then lower the amp signal slow and sensitively to get the audio volume to correspond to the led brightness. currently, i dont know how transistors arre different from one another, mine has no numbers whatsoever

[thegeeke]

When music sync. lights are steady it means you have the volume to loud. I would worry about not bursting your speakers before you try to add on a sync. light. -A pro. sound and lighting designer

[nyxynyx]

im using C547B for the npn and LM340J5 for the voltage regulator. I've tried 12V and 5V voltage sources.

[bmxlive]

Will a TIP31C transistor work whit a 12volts led? I'm thinking that it´s dosn´t work because of it, all examples are made with lower volts LEDs, so can anyone told which transistor I might use please!

[cookn]

That lm340 is from national and is a positive voltage regulator so your diagram is wrong you are using it like a negative regulator

Data sheet:
http://www.national.com/mpf/LM/LM340.html

[optimized4perfection]

haha, at first i thought it was a transistor cos it had 3 pins, thats how much i know

[cookn]

npn or pnp transistor?

[tinkerman92]

ive got many things to take apart lol so i can just get some and also get some off my friend u think it could hold about 100 leds? lol if so ill make a giant 1 lol

[optimized4perfection]

right now im running 40 off a phone charger no prob. if i make another one ill try to get the uber bright ones whicha re supposed to be at least 10 times brighter and supposedly also 10 times more expensive and difficult....

[tinkerman92]

um ok i got an experiment kit u know were they throw in a bunch of transistors capicitors ect i can easily identify the items i need but can i build 1 with it? i dont like wasting money

[optimized4perfection]

sure. it will work as long as there is a transistor and you get the volatge right for the power source and the amp is of the right power

[tinkerman92]

lol ya i got it working without a transistor but ill have to get some blue leds cause red suck but all u need is 4.5v its wat i used then an amp which idk how to wire up my dual co amp thats in the kist so i used a headphonejack splitter that has built in amp thats about it i can take pics if u want when i get leds ill make a plexiglass 1

[optimized4perfection]

how does a headphone jack splitter have a built in amp? i made one without the transistor at first but it wasnt very bright especially for blue leds

[tinkerman92]

the head phone jack splitter ur splitting 1 line into 4 so u also r splitting the power so it just adds it lol i ment i got it working without the thermal circuit or the regulater i used a transistor still but the thing is im afarid to put too much power threw the transistor and 4.5 v its only enough for like 1 led so wat can i do?

[optimized4perfection]

4.5 volts is fine, my transistor (the small kind) can easily take 20 leds so its fine. there will be enough power if the leds are in parallel but since u only have 1 led (lol) then nvm