Digital Color Organ

[Mutie]

Here is a link to an updated schematic. BTW that line that connects R1, 3, 9, 16, and 14 should go to +9V.

And here is a 3.2 MB pdf very poor quality 3rd or 4th generation copy of the original article from the July 1980 Radio Electronics.

I originally built this circuit back in 1981 or 1982 using some of the first water clearm high brightness LEDs of maybe 20 or 30 mcd if that. I also dropped R4 and R5 and cascaded 2 additional 4017s so it was running 90 LEDs. It was quite an amazing display although not nearly as bright as I would have liked. In researching the specs of the LM3915 and 4017 it appears as if the LM3915 can supply up to 30ma which is fine, but the 4017 handles less than 1ma which would explain why it isn't as bright as I would like and why no resistors were required on either side of the LEDs.

I'm thinking of putting in a ULN2803 on the outputs of the 4017 so that I can get some decent current and using dropping resistors to get what is needed and using ingan green and blue LEDs this time. Is this workable? I will probably also go to 5 steps off the LM3915 so I can use blue, green, yellow, orange, and red LEDs.

I would also like to come up with a version of this circuit that would drive 1w Luxeons. But I'm not quite beyond my electrical knowledge to do so. I think it could be done with NPN and PNP transistors off the outputs of the LM3915 and 4017 respectively with the collectors going to the LEDs and then the + and - of the battery and whatever dropping resistor but as I said it's a bit beyond my depth and if possible I would prefer using chips as opposed to discreet transistors.

If I can get all that working I would also like to consider getting some printed circuit boards made up as I know I would end up making at least 5 and probably more for costume as well as display applications. Can anyone direct me to a source to get this done?

Any advice would be much appreciated. And I highly encourage anyone to build on an experimenters board. It is easily the coolest color organ I have ever seen.

Thanks,
Mutie

 

[WildRice]

a GREAtT modification to this circut might be to replace the LED array with RGB LEDs... CAUTION.. (I got stung on this, I got some RGB's from EBAY for a project they were common annode, I needed some more and the second set I got from a different person and they were common cathode... ask beforehand. the common cathode (-) were from Hong Kong)

Jeff

 

[Mutie]

WildRice,

If I was using this as a stereo display that would be a great idea. And actually for part of the display that sounds like an interesting idea as it would generate multiple color combinations depending on the input signal.

In actual use this circuit will be designed into some costumes and sensors.

Mutie

 

[Mutie]

Bump.

Anyone?

Bueller, Bueller?

 

[WildRice]

BUMP, hey has anyone built this yet? I now have a lexan tube about 8" in diameter and about 4feet long. I have already started sanding it with 60grit in the long direction only to gife the effect of a broad linear viewing angle. I have enough 3mm red blue and green LEDs as well as the chips. Just want to find out if the effect is cool or not.

Jeff

 

[SemiMan]

Did you document that original LED color organ? It seem that Color Kinetics is trying to patent that same basic idea as the color organ just using LEDS (well and anything else under the sun that has been done with traditional lighting technology). Some company may be interested in your work for a defence.

 

[WildRice]

Naw, I just found it here from Mutie. I ended up using some 74XX244's octal buffers on the 4017 and the 3915 and just reversed all the LED polarities. The LEDs are brighter now and the string of RGBRGBRGB LEDs in the frosted tube looks really cool. All I need to do now is to breadboard the circuitry. Right now it is on proto-board.
Jeff