[PD] control lot of audios files with arduino + puredata

[Martin Peach]

On 2011-05-29 23:20, FernandoG wrote:
> Hi
> i need to design a sistem to control 40 diferents audio files and
> playback in a stereo sistem. I was thinking to use puredata and arduino,
> load the 40 audios in a pd patch and use 40 switches and resistors into
> some arduino inputs to trigger and playback any of the 40 audios in pd.
> Every switch will be conected to a diferent resistor to  generate
> diferents voltages then arduino inputs can diferenciate witch audio to
> playback. Also i need to power on a led any time a specific audio is
> been playback. The 40 audios will not be playback simultanusly, but
> probably al least 15 or 20 could be.
>
> Anybody knows about a similar proyect? can i use analog input to control
> various samples or its not good idea? multiplexors? do i need to use an
> arduino mega or its not necesary?can i power 15-20 led simultaneously?
> the best way to do this system stable for long long time?
>

The analog input method is similar to the resistor ladder that analog 
synthesizer keyboards used. Arduino analog inputs can differentiate 1024 
levels but the values of resistors are usually 5%, but 40 levels should 
be easy.
The best way to do LEDs is with shift registers. That way you can use 
just 3 pins on  the Arduino to control as many LEDs as you like.
For LEDs use parallel-output shift registers, like the 74HC164. Also the 
input could be done with parallel-load shift registers (for example the 
74HC165), but the resistor method is cheaper.
It should be quite stable over time.

Martin