COLORORGAN

Joseph R. Groele

Topic: Physics - Electronics

Purpose:

Design a portable color organ that will take the frequencies from a song and represent the music using three differently colored LEDs.

Hypothesis:

If the circuit is built correctly, when music is played, the LEDs should light up in accordance with the frequencies in the songs. Red will represent the treble frequencies, blue the bass, and green the midrange.

Project Outline•Define the project•Research and order parts•Analyze options and design circuit

•Construct circuit•Test and modify

Procedures:1.) Solder the LEDs together in the desired pattern, paying

attention to where each color LED is being placed.

2.) Connect the spaces between the LEDs to form the bar graph ladder circuit.

3.) Solder all connections and test before proceeding. 4.) Assemble the filter circuits and insert in the remaining

spaces between the LEDs.

5.) Construct a circuit board to mount the microphone and trimmer potentiometers. Test connections again before proceeding.

6.) Complete the preamp circuitry and the rest of the wiring.

7.) Mount the circuit board and circuit assembly to the battery case.

Materials• Solder• Soldering Iron• Wire• Wire Strippers/Cutters• C Cell Battery Holder• Perf Board• 1.0K Ohm Audio Microphone• 50K Potentiometers• 200K Potentiometers • .01 uF Capacitors• .1 uF Capacitors• 1000 pF Capacitors• 2200 pF Capacitors• 4.7 uF Capacitors• 47 uF Capacitors• 220K Ohm Resistors

• Blue Water Clear LED• Green Transparent LED• Red Transparent LED• 33K Ohm Resistors • 2.2K Ohm Resistors• 100K Ohm Resistors • 4.7K Ohm Resistors• 10K Ohm Resistors• 47K Ohm Resistors• 470K Ohm Rresistors• 100V Diode• PNP Epitaxial Transistors• 200mA 60V NPN

Tranistors

Color Organ• A color organ is an electromechanical device that

is used to represent sound or accompany music. They respond to frequency inputs with exhibits of light that flash along with the music. The display device uses a plurality of light bulbs, in this case LEDs, which are set in distinct groups.

• Each group of LEDs is illuminated as a response to a corresponding frequency range of audio input. The brightness of the LED is directly proportional to the amplitude of the signal coming from the corresponding frequency channel.

Conclusions•The potentiometers need to be adjusted to

each song and each volume to achieve preferred results.

•Adding more LEDs should produce a more interesting light display.

•When the circuit is attached to a 555 Audio Oscillator circuit, the ‘frequency in’ displays a measurable input frequency, but the ‘output voltage’ is not defined enough for accurate measurement.