The circuit, sketches and process described here will allow you to produce melodies using an Arduino and a VCO.   The sketches provided already have the melody for Mary Had a Little Lamb.  You can easily change the melody in the code and potentially build upon this project to make polyphonic music with one Arduino and six VCOs.

Materials needed:
• Arduino and USB cable
• Breadboard
• Potentiometer
• 8Ω Speaker or connection to an audio amplifier

• VCO & Low pass circuits
  1x 7555 Timer
  2x 10kΩ Resister
  2x 1kΩ
  1x 1µF capacitor
  2x 100µF capacitor

• Guitar tuner, Musical Instrument or well trained musical ear.

Step 1: Build VCO Using 7555 Astable Oscilator

Use wire diagram below to build the VCO on your breadboard.   Though not pictured, please connect the 5v pin from the Arduino to the Vcc rails on your breadboard and ground on the Arduino to the ground rails on your breadboard. 

very cool! what do you want to use this for? would be cool to use the arduino as a midi to cv module
indeed. effectively that is what this circuits produces; CV for the 7555. With a few modifications you could certainly produce CV with the PWM outputs of the Arduino. Likewise, you could use a digital potentiometer controlled by Arduino, which could in turn be controlled by MIDI. If you have a minute, please checkout this one: https://www.instructables.com/id/MIDI-controlled-analog-FM-synthesizer/

About This Instructable




Bio: Music Technology at NYU Steinhardt is a leading and internationally recognized program in music, sound and audio technology. Students prepare for successful careers in sound ... More »
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