Scott S

Would it be possible to use one pot for the whole thing ? It would be easier to make each color the same brightness that way. Also, would this peak detector work: http://freecircuitdiagram.com/2008/09/07/single-transistor-half-wave-peak-detector-circuit/ Would it be possible to also have 1 peak detector for the whoe thing ? Thanks for your help

would I put the pot before the first capacitor ?

nevermind, I figured it out, but it is somewhat "blurry". would a peak detector help this ? Can you reccomend a peak detecting circuit ? Where would I attach it ? Also I notice that as I turn the volume up, the leds get brighter. Is there a way to adjust this so that it would be as bright at listening volume as they are on max volume ? I plan using a splitter and listening while it blinks. Thanks for your help

I can't get it working. I'm trying the left channel with only one led, trying to start small. Everything seems to be connected correctly. I'll list the components I'm using, maybe one isn't correct. 35v 10uf cap, 2n3904 npn, a 22 ohm resistor, 150 ohm resistor, and a IN4003 diode. Is there any common noob mistakes that I may be making ? Thank you for your time.

I have a noob question. How does the transistor control the leds, when the leds are connected to the battery and the transistor is connected to the leds ? sorry for the noob question.

Did I correctly fix the circuit ? Thanks for your help

The voltage is at 6 volts, and the main resistors are 22 ohms. The two capacitors arer also 10 uf, like you suggested. So, the olnly thing I have to change is the resistors in front of the leds ? Also do I have the ground connected correctly ? I wasn't sure if that was where it went or not. Thanks for your time.

Is the circuit now correct. Thanks

Wouldn't the 7.5 volt circuit last just as long as a 6 volt one ? The 7.5v draws 200mA, the 6v draws 400mA. 7.5v: 200mA drawn until 6v would last roughly 4 hours. 6v: 400mA drawn until 3v would also last roughly 4 hours. I'm not trying to start an arguement, just trying to point that out.

sorry i was looking at two differnt post and replied to the wrong one. once again, sorry. :-[

Wouldn't the 7.5 volt circuit last just as long as a 6 volt one ? The 7.5v draws 200mA, the 6v draws 400mA. 7.5v: 200mA drawn until 6v would last roughly 4 hours. 6v: 400mA drawn until 3v would also last roughly 4 hours. I'm not trying to start an arguement, just trying to point that out.

I have attached an updated circuit. Is everything correct in the schematic ? Is there anything i can do to the circuit to have the leds blink at listening volume as they would blairing, as I would like to attach a splitter so I can listen to headphones while it blinks ? I found a few "simple" peak detector circuits. If I decide to use one, would I put it before the capacitor ? I would use 2 of them, correct ? Would the results of the peak detector be worth installing it ? Also, would either the 2N3904 or the 2N4401 transistors work ? Thank you for your time, I really appreciate it.

Thank you for pointing that out audioguru. I have attached the schematic. Can you explain how I can alter my circuit to include the peak detector circuit ? Thanks

I found 2 transistors that are similar to the BC548 in your schematic, the 2N3904 and 2N4401. The only difference between the two, that I could find, is the collector current. The collector current of the 2N3904 is 200mA, while the collector current of the 2N4401 is 600mA. Would it be better to have a higher or lower collector current ? Another noob question: What is the importance of capicators ? Here is a schematic I made. http://www.flickr.com/photos/51872883@N08/4769178237/ Is this correct, or is there something i forgot to do ? Thanks for helping

Am I going to have to use 2 transistors since there's gonna be 20 led's in the circuit ?

Would I be able to get half of the leds to respond to the right channel and the other half respond to the left channel, while powering the leds from the some power source ? Again, thank you

Accordng to this schematic where do the 3 individual wires from the audio input go ?

Also how bright of leds you you think I should use ? Thank you for your time

does voltage of the transistor matter ?

is there a similar transistor ? I can't seem to find that one locally, in North America. once again, thanks for your time.

In your circuit, will the leds get brighter as the music gets louder ? I just thought of that idea, to me it might make it look better. How could I modify your circuit to adjust the brightness of the leds to the loudness of the music ? thanks for your time

I am in the process of designing a necklace with about 20 leds, give or take a few. Thats all fine and dandy. I am trying to design the necklace so tha the LEDs will light in response to music. The music wil come from an mp3 player, via a stereo cable. I am having trouble designing a circuit that dosen't take much space, and will accoplish the goal of blinking the leds in response to the music. It would be nice to have the leds get brighter as the music got louder, if possible. The circuit will be eitther be powered by AA batteries or 3v 2032 bats, not sure yet. Half of the LEDS will be white, and the other half will be blue. Also i was thinking of putting clear beads over the leds. Would this wash out too much of the color from the leds ? One more thing, would it be better to use a cat5 ethernet cable or speaker wire ? Can anyone help me design this necklace ? Thanks Scott