smallest 5 led mono vu meter circuit diy?

[Mustachio]

I ended up trying to make my very first pcb layout from this thread with the an6884. Used expressPCB and did 10 leds total like how you had mentioned earlier dead. I gotta say it works really nice I dont have any issues with any leds staying on or not triggering well. Its pretty much great and very responsive! love it! 



and heres pre assembly its the board on the right.
I will say the traces and pads where very small, didnt realise till I went to drill it after etch. I went back and fixed in expressPCB for the next time I etch one. If you want the layouts let me know. Thanks for all the info on this was awesome I love leds and vu meters!



Also I never had any luck bread boarding the lm3916 with an opamp in front of the input. Ive only gotten it to work with guitar straight in with a very small limiting resistor . Ill work on that more later. Thanks again for all the info guys !

[deadastronaut]

^  COOL.... thats a neat little ic eh!....cheers to gurner too!...

[Mustachio]

Yeah its awesome I think I picked up 4 or 5 gonna have to get more, been seeing a few different circuits for it online I think one was a spec analyzer. I love these led circuits I just picked up some of those 5 meter flexible led strips now I wanna try to make a vu circuit for that!

Here's the PCB and layout images. 300 DPI should do it

[deadastronaut]

5 metre strips?....nice!!!...ive got to see that...

[Mustachio]

Ah if you havent seen them , they make a few diff kind the ones I got are 5050 type rgb non water proof they look like this and come on a reel at 5 meters



they make others that have an IC every led and you can control each led separately they are called dream color some times if you wanna look for those their more expensive but look for the led strips called 6803

the 5050 are on off or fade because of the way their made and no ic controller per led.

They come in water proof too and look great behind crown molding!

usually a 5m strip takes about 2-3 amps so I'm going to try to figure out a route to control R/G/B separately from audio input .

[deadastronaut]

cheers jim, looks great, keep us posted with this...i'm an led junkie too...  nice one!.

[deadastronaut]

in my missus's infinite wisdom ...we are having an 'end of the world/sci fi '' themed party on the 21st dec..

my task for this is to make a ''big'' (i mean full size 7-8 foot robot. )  cheesey made from cardboard and silver foil really,  to stand in my hall , ive collected various bits n bobs and boxes to make him already..

anyway to the point, using the an6884 vu meter setup, which is brilliant btw... i would like it to be sound to light, (for his mouth or eyes) (i'll diffuse the leds behind a strip of sanded perspex..)

i have a small electret mic, 
http://hades.mech.northwestern.edu/index.php/Microphones

would this  circuit be fine going into it?......and able to be audio sensitivity adjustable. the more sensitive and simpler the better really..(its not going to be a permanent fixture.....erm.....well maybe )

2nd circuit down...

http://www.head-fi.org/t/547933/q-how-to-modify-mic-pre-amp-to-higher-gain

[Jdansti]

in my missus's infinite wisdom ...we are having an 'end of the world/sci fi '' themed party on the 21st dec..

Cool!  Thanks for letting us know!  Please tell your "better half" that we'll all be there!!!   

[PRR]

That will work.

Change the 10K biasing the capsule to a 10K pot, wiper to capacitor, for sensitivity. (Scratch is OK.)

Suggestions:

Use a Darlington, change 100K to 10Meg.

Should I bring a casserole?

[deadastronaut]

@jon:  ok, i told her, she said she would put out some bowls of chips to nibble on then......

@paul:  cheers, i used a darlington mpsa13 and 330k...2x 5 3mm blue leds......it works and looks great and is very sensitive...however, it flashes when putting a  sine wave into it rather than just holding at that level.....

how can i smooth that out...?


re: casserole:  yes please...and lots of beer!.

heres the schematic i drew up..

[Jdansti]

re: casserole:  yes please...and lots of beer!.

heres the schematic i drew up..

Since Paul has the casserole, I'll supply some Shiner Bock beer from central Texas.   

[R O Tiree]

No schem shown, Rob...

As long as we're having a pot-luck supper, how about I bring dessert?  Mississippi Mud Pie, anyone?

[deadastronaut]

@mike:

hi mike, scheme shows up for me?...anyone else not see it?

https://dl.dropbox.com/u/7464107/micvumeter1.jpg

[PRR]

> it flashes

I suspect this will be acceptable for the purpose.

But let's think "why?" anyway. Put in signal. LED(s) light up, draw current. Power source sags suddenly. Q1's bias changes suddenly, it doesn't work until it self-corrects. Meanwhile loss of signal through Q1 has turned-off the LED, the current, the sag.

Mike preamps should generally have decoupling in the power line. 1K and 100uFd might be ample here.

[R O Tiree]

> hi mike, scheme shows up for me?...anyone else not see it?

Bizarre... it's there, now.

> Mike preamps should generally have decoupling in the power line. 1K and 100uFd might be ample here.

??  Did you mean "Rob"?  All I wanted to know was if anyone wanted Mississippi Mud Pie for afters

[PRR]

> Did you mean "Rob"?  

"Microphone preamps bla-bla". Wasn't calling you. Sorry. Too much chocolate.

[garcho]

they make others that have an IC every led and you can control each led separately they are called dream color some times if you wanna look for those

You mean they make those in more colors than just 'information kiosk white'?

[deadastronaut]

tried the cap/resistor...no joy...

its ok for drums, it picks out the kick nice, but its quite annoying when music is playing that it just flashes constantly at a regular freq..

i tried tweaking the AN6884  10uf/10k..and the 2.2uf.....well all of it really...

...i'll try a few more tweaks.......heres my plans anyway...

i made it modular so i can use the bits later...no cuts either whooohooo   

[Jdansti]

Extra points for no cuts! 

BTW- Don't you think you're robot needs a voice?  Maybe rig up one of those voice recorder/players from a greeting card to a motion sensor so that when someone enters, the robot greets them?  When he talks, his "voice" will also activate your LED circuit which will flash as he speaks.  You'll have to run your voice through one of your DIY filters when you record it to give it a "robotty" accent.

[deadastronaut]

ha ha cool idea, but i don't think you'd be able to hear it above the carcass, slayer, opeth, kreator, negura bunget type thrash...