[PD] Sensors

Marc Lavallée odradek at videotron.ca
Fri Oct 31 15:01:34 CET 2003

On Fri, Oct 31, 2003 at 09:25:34PM +0800, Chris McCormick wrote:
> An idea I had recently (though I'm sure it's not original) is to hook up
> 8 555-timer circuits with variable resistors to the parallel port and
> poll it periodically to figure out the frequency of the 8 squarewaves on
> individual parallel port pins.
> These frequencies could be used as control values in a Pd patch. The
> advantages are that 555 timer circuits with a variable resistor are
> very cheap, and simple. Your range would be from where frequency updates
> are too far between (let's say 100Hz) to the upper-range of the parallel
> port polling frequency. So if you can poll it at 8000Hz you would
> probably want to stop at nyquist to get meaningful updates let's say at
> 4000Hz (not quite certain that nyquist is relevant here though).

Interesting, but I'm not sure it's possible to poll the parallel port as 
fast. With my parapin object, I use 1Khz by default, which correspond to 
the maximum resolution of timers in PD (but I might be wrong).

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