Circuit Skills LED Color Organ
Add synched visuals to your hi-fi experience.By Collin Cunningham
Adapted from Aaron Cake's 3 Channel Spectrum Analyzer, Collin Cunningham designed an analog schematic for the LED Color Organ to enhance the aural experience. The circuit uses four operational amplifiers plus ultra-bright 5mm LEDs to respond visually for bass, mid, and treble frequencies.
Long before the dawn of digital music, folks employed the power of the electric color organ (aka "light organ") to add some synched visuals to their hi-fi experience. Schematics for building such a beast based on AC power and incandescent bulbs can be found fairly easy on the Web, but plans for comparable LED-based designs seem a bit harder to come by.
To build your own LED Color Organ, we have a couple of options for you.
Step 1: ICs U1, U2Take note of the orientation of the ICs and IC sockets by looking at the notch and matching the notch of the IC to the notch of the PCB. See Figure 1.
Figure 1: IC Polarity
Step 2: Diodes D1, D2, D3The correct configuration of the diodes is shown in Figure 2. Pay attention to the stripe on one end of the diode indicating the cathode end.
Figure 2: Diode Polarity
Step 3: Transistors Q1, Q2, Q3Polarities of the Bipolar Junction Transistors (BJTs) are extremely important. Here, we use the 2N3904, 3-pin package. Match the component to the symbol in Figure 3.
Figure 3: Correct BJT Pinout
Step 4: Non-Polarized Resistor Color CodeR1, R2, R3, R16, R17: 1kΩ (Brown, Black, Red)
R4, R5, R6: 560k1kΩ (Green, Blue, Yellow)
R7, R8, R9: 6801kΩ (Blue, Gray, Brown)
R10, R11, R12:/ 39k1kΩ (Orange, White, Orange)
R13, R14, R15, R27, R28: 100k1kΩ (Brown, Black, Yellow)
R18, R19: 4701kΩ (Yellow, Violet, Brown)
R20, R21: 1601kΩ (Brown, Blue, Brown)
R22: 1M1kΩ (Brown, Black, Green)
R23: 47k1kΩ (Yellow, Violet, Orange)
R24, R25, R26: 20k1kΩ (Red, Black, Orange)
Step 5: CapacitorsC1 through C7, C15 non-polarized capacitors.
C1, C2 0.0022µF
C5, C6: 0.047µF
C7, C15: 0.1µF
C8 through C14: These electrolytic are polirazied with the negative side (shorter lead) indicated by a strip on one side, see Figure 5.
C8, C9, C10: 2.2µF
C12, C14: 4.7µF
Figure 4: Electrolytic Capacitor Polarity
Step 6: LEDsD4, D5, D6, D7: Yellow (represents the Treble)
D8, D9, D10, D11: Red (represents the Mids)
D12, D13, D14, D15: Blue (represents the Bass)
Be sure to have the cathode end (shorter lead) facing the side with the flat edge. See Figure 5.
Figure 5: LED Polarity
Step 7: Audio Jack and Power Jack U4, U5There is only one way to insert each of these components into the board, so just be sure to apply enough solder to ensure a good connection with each tab.
Figure 6: Audio Jack Pinout
Figure 7: DC Power Jack Pinout
Keep in mind that this project makes a mono-channel LED light organ, which means if you plug in your headphones, music will only come out of one side. If you wish to make it a stereo light organ, you will have to duplicate this circuit for the second channel. As always, remember to take extra precaution when soldering! Most importantly, have fun!
Click here to enlarge
We would love to hear how your build turned out. Let us know at [email protected].
Other Circuit Skills DIY Videos by Collin:Circuit Board Etching
Function Generator and Enclosures
Infrared Light Barrier
LED Matrix Kit
Pulse Width Modulation
Surface Mount Devices