nitro2k01 investigates using the versatile Arduino platform for use as synthesizer modules -
The idea of using my Arduino for modular synth utilities started out as a crazy idea that Iâ€™m now starting to seriously like. The pictures above shows my first design, an oscillator. (I have plans for other modules, see the bottom of this post) The left picture shows the first prototype where I tried to use PCM to produce the sound. That didnâ€™t sound too good, so I built an 8-bit resistor ladder passive DAC. But I only hade enough of one resistor value, so I used only that value. This gives a non-linear output voltage response. (Distorsion) Additionally Iâ€™m only using 6 of the possible 8 bits, further degrading the sound quality. The input voltage response does not conform to any standard (Eg 1V/octave) but has a inversely proportional relationship (f(V)=c*1/V, where V is the voltage, c is some constant and f is the resulting frequency) This relationship is not completely unlike how a Gameboy responds to sound values that you write to itâ€™s sound controller. However, surprisingly enough, it seemed almost impossible to hit musically dissonant intervals, so it seems like I did something right.
Definite potential for this application – a control voltage sequencer should be pretty straightforward to implement. Check out the site for detailed samples, analysis, and ideas for future iterations. – ModularDuino