To create a polyphonic musical instrument using the Arduino Duemilanove. The Arduino isn’t fast enough to create multiple interesting waveforms and simultaneously control other stuff (I still have to look into this, be for now it’s a safe assumption) so I’ll be using a XR2206 function generator to create the waveforms. The Arduino will control one (or two?) function generator per voice.

The VCF (Voltage Controlled Filter) is on order from HongKong – four SSM2044′s. A classical VCF used in vintage Korgs like the polysix and the mono/poly.

Haven’t though about the VCA yet, probably a LM13700 OTA or a MCP42100 digital pot.

Arduino is gonna keep track of settings and presets etc. I’ll probably be needing some extra memory… All settings are controlled via digital pots. These on their turn are controlled by rotary encoders. A LCD will show all settings (it’s already working).

To get the maximum from the limited number of Arduino pins, I collected some CMOS logic chips like the 4066 (quad bilateral switch), the 4021/4094 (8-bit static shift register) and the 4051 (8-channel multiplexer).

It’s gonna be a challenge to keep the whole instrument musically tuned but I’ll probable run into that during the project. Once’s build, I can always replace the function generators etc with DSP units or something like that.

BTW: read the article by Gian Pablo titled “Generating polyphonic sound with Arduino“. I got some great ideas from it.

sinneb@gmail.com