Hi Mike,
I do not understand how you wired the LEDs and why you did not use the current limiting resistor and the transistor.
Please sketch how you have it wired.

__________________
Uncle $crooge

 

would the transistor crkt work with 2 LED's in series and no speakers without the pot?
i wired like this:
_______
+ l-------l\ l
AMP l l \l___
CKT - l-| l /l l
_______l | l/ l l
| l
|__________l

With multimeter:
____________________
l +multimeter
_______ |
+ l---|---l\ l
AMP l l \l___
CKT - l-| l /l l
_______l | l/ l l
| l____________-multimeter
|__________l


Sorry if its hard to understand, paint isnt working

EDIT sorry, looked different when i was typing it


baisicaly this:

Amp output (+) ---> LED +
Amp output (-) ---->LED -

With multimeter:

Amp output (+) ---> LED + ---->Multimeter +
Amp output (-) ---->LED - ----->Multimeter -

 

The LM386 amp doesn't have a (-) output so maybe you are using a different amp.

Without a speaker to discharge the 470uF output coupling capacitor, it will become charged and cause the transistor not to work.

__________________
Uncle $crooge

 

it may just be the negative terminal of the power supply because there is a 3.5mm jack and then 2 solder pads, one with + and one with -

is there ANY way to have the LED's to flash at a decent brightness without speakers?

can i get rid of the cap and put a jumper wire there?

 

This circuit will flash its LEDs with the music. It has an extra 10uF cap for more gain. It probably won't work with a supply voltage of only 7.2V from a rechargable or run-down battery.

Attached Images

leds_flash_to_the_music.png (15.5 KB, 689 views)

__________________
Uncle $crooge

 

ok, thanks.... i have my new antex soldering iron now so i think i'll give it a go

 

]

Yea im saving up for one of those as well....the 110V input version though that

__________________
Dave

www.myspace.com/sonicorbstudios

Welcome to "Sonic Orb Studios"

 

i have that one (240v i think) i got it for £9.99 on promo :P

 

Audioguru, I've setup your last diagram you posted for Music player's input with the 10uF cap between 1 and 8. I'll admit I'm no expert electronics person. I used to be out of college, but when you don't use it you lose it. The way I have it setup is taking sound out of a laptop and splitting it, one connection to your circuit and the other to speakers. It works fairly well, but the leds are almost always on. I would like it to be more sensitive to the beat of the music and not so much just any sound coming through. What part of the circuit do I need to modify to get closer to this effect?

Also, I'd like to add quite a few more led's than just two. I've read some of the posts, but am still unclear. If I'm using an actual plugged in constant 9v power source (not battery), can I just keep adding multiple parallel sets of led's with a resistor in series with each of them. How would I calculate what kind of resistor I need?

I appreciate all your posts and any help you can give me.

Thanks,
Ryan

 

the 100k pot is used to control the sensitivity, try changing that for a larger value, e.g a 1M

 

Don't change the pot for a higher value. Just turn it down. If the pot is turned down very low and the circuit is still too sensitive then remove the capacitor between pins 1 and 8 of the LM386.

The LM386 is sensitive to all sounds that are in the music. If the music has a bass beat then adding a lowpass filter to the circuit will allow it to blink the LED to the beat of the music.

My new Sound Level Indicator project:
http://www.electronics-lab.com/proje...009/index.html
has an LM3915 driving 20 LEDs in 10 steps of level. It has automatic-gain-control so it usually indicates conversation voice levels but cuts back to show the beat of the music.

Attached Images

sound_level_indicator_002_212.jpg (47.1 KB, 517 views)

__________________
Uncle $crooge

 

Hey audioguru, I was looking for a circuit to replace those really expensive DJ lights that get hot and use fragile light bulbs. My plan is to use the above "LEDs flash to the music.PNG." I was thinking of using three lm386's, with each one attatched to a pass-filter (low, mid and high). Also, I wanna have each lm386 run 12 high-output single color ed's (6 + 6, for both high-low ouput @ PIN 5). It'll be fed by AC via an powersupply so any extra juice is no problem. I'm gonna try to keep cost down and use surplus, since most part are cheap. In case you are unfamiliar with the type of lighting I'm refering to, check out the most popular unit, Vertigo, by American DJ I know basic electronics, but I got no way of designing this. Thanks for any input!

 

Hi Simple,
Vertigo uses 600W of power for his lights. Your idea to use three sets of 6+6 LEDs will have half the LEDs turned on at any moment, so the total momentary LED power is only 1.5W.

The problem with your idea to use LEDs is that the LM386 has an output of only 1/2W and "ordinary" LEDs are each rated at only 60mW.
Amp ICs for car radios can drive 20W and very powerful 5W LEDs are available that will work much better.

__________________
Uncle $crooge

 

check out these LEDs: http://www.allelectronics.com/cgi-bi..._T_1-3_4_.html. Can't some sort of simple buffer be used in between the IC and the LEDs? Also, isn't there away to connect LEDs in sinking mode? In sinking mode, you don't have to worry about the maximum current output of the IC. So, the only thing that would have to be changed in this design is the placing of the resistor and adding Vcc instead of ground. And of course, the frequency filters still need to be designed.

For info. on sourcing/sinking, see A typical LED and its schematic symbol in this website: http://www.pond.ie/techinfo/x000/index.html. It's a pretty common technique to use when dealing with ICs, and that's what we have been using in my intro. to digital circuits course.

Take care!

 

It is an ordinary white LED like used in key-chain flashlights that is not very bright. This one has a very narrow beam.

The absolute max current for that white LED is only 20mA which can easily be supplied by an LM386.

An LM386 sources or sinks enough current to drive 18 of those white LEDs to their max current. That is only 1.3W which is nothing when compared to a 600W light.

__________________
Uncle $crooge