Color Organ Page


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NOTE: an all new 8 channel color organ design is available. Check it out here.

A color organ is a device that splits music up into numerous frequency bands and modulates colored lights (typically one color of light per band) according to the musical content. I used to build them in my younger days for use when listening to music and for some of the bands I was in. Color organs were part of the "scene" in the 60's and 70's.

I designed this color organ from the ground up using digital technology instead of the more traditional analog technology typically used in color organs. After I got the color organ to work I wrote a series of three articles for Nuts and Volts magazine that discussed the technology and the implementation of the color organ. These articles appeared in the Sept 2007, Nov 2007 and Jan 2008 issues. Nuts and Volts magazine is available in the Pikes Peak area libraries. If you would like to read these articles they are available here.

September 2007 Floating Point Multiplication and Division without Hardware Support
November 2007 Lattice Wave Digital Filters
January 2008 Psychedelia II - A Digital Color Organ



Here are some fotos I did for the article which shows how the color organ was constructed.

controller
Here is the main color organ circuitry. The micro controller which runs the color organ is on the blue board at the left.
wiring
The complete color organ was built onto the back panel of a triangular display box I bought at Hobby Lobby.

The LEDs are the super bright variety that are bright enough to be seen easily in daylight.


back
Here is the back of the finished color organ. Here you can see the control panel.
front
Here is the front of the color organ. It turned out nicely I think.

The color organ has a micro controller (computer) for a brain. This chip is smaller than the nail on your little finger. I purchased a development kit for this little micro for $20 from Texas Instruments (www.ti.com). The complete development kit is built into a USB dongle which is amazing in itself. The photo below shows you the scale of what I am talking about. With the $20 development kit (which includes an assembler, linker, C compiler and debugger), TI has truely brought micro processor development to the masses. The micro controller target board is in the top left and the development kit is at the bottom.

target board




Below are the schematics and parts list for building the color organ.


main
output

Parts List

Part Designation

Value

Notes

C1,C4,C5,C6,C8

4.7 uf capacitor


C2,C13,C15

0.1 uf capacitor


C3

230 pf capacitor


C7

0.022uf capacitor


C9

0.01 uf capacitor


C10

0.02 uf capacitor


C11

0.04 uf capacitor


C12,C14,C16

47 uf capacitor

polarized

R1

4.7 K resistor

w 5%

R2,R6,R7,R8,R13,R14

1 K resistor

w 5%

R3,R4,R9,R10

20 K resistor

w 5%

R5

1 Meg trimmer

10 or 20 turns

R11,R12

1.6 K resistor

w 5%

R15

270 ohm resistor

w 5%

R16,R18,R20,R22

470 ohm resistor

w 5%

R17

22 ohm resistor

1 w

R19

18 ohm

1 w

R21,R23

6.8 ohm

1 w

D1

1N5819 diode

Optional reverse voltage protection diode

D2,D33-D42

Superbrightleds.com Blue LED

RL5-B4630

D3-D12

Superbrightleds.com Red LED

RL5-R5015

D13-D22

Superbrightleds.com Yellow LED

RL5-Y5030

D23-D32

Superbright.com Green LED

RL5-G5023

J1

Stereo 3.5 mm / 1/8” jax

Line input connector

J2

2 wire power jax

Optional

J3/J4

Inter board connections

Optional

M1

Condenser microphone

Jameco #160979

Q1-Q4

2N4921 switching/power transistor

Heat sinks aren't necessary

SW1

SPDT

Mic/line switch

SW2

SPST

Power off/on switch

U2

LM2940CT

5 volt 1 amp voltage regulator

U3

LM3940IT

3.3 volt 1 amp voltage regulator

U4

MSP430-F2012

uC target board. Available from TI.com.

U1

LM324

Quad op amp

U5

74HCT139

2 to 4 demultiplexer

U6

74HCT04

Hex inverter/buffer




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