LED flasher to music (needs improving... transistor help)

[audioguru]

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:
https://www.electronics-lab.com/projects/motor_light/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.

 

[simpleinventor]

DJ equipment

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!

 

[audioguru]

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.

 

[simpleinventor]

check out these LEDs: http://www.allelectronics.com/cgi-bin/item/LED-75/340500/ULTRABRIGHT_WHITE_LED,_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!

 

[audioguru]

check out these LEDs.

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

Can't some sort of simple buffer be used in between the IC and the LEDs?

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

Also, isn't there a way....

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.

 

[neon]

i did not read all of the replys but it seems to me that the problem is adjustment . LEDS are diodes and are min voltage sensitive and current sensitive in other words the more the current the more they becomes bright the trick is not to destroy them by over power dissipasion. i have biuld for christmas 115 v ac to music lights using triacs LEDS ARE ALL STRUNG IN SERIES using 2 v average per unit but i put a current driving source to limit the current safely now no matter where the music is set they light up by adjusting the unit value input.

 

[audioguru]

Hi Neon,
How did tou isolate the input of your circuit from the mains?
A microphone or a transformer?