[PD] Sensors

[Hans-Christoph Steiner]

Actually, USB mice can have quite good resolution and sampling rates.  The
problem is the OS drivers limit the resolution to screen pixels but
there are tricks to get around that.  I think the sampling rates are on
the order of 1-5 khz with a resolution of 400-800 pixels per inch.

http://www.semiconductor.agilent.com/cgi-bin/morpheus/home/home.jsp?pSection=Optical+Navigation

.hc

On Fri, 31 Oct 2003, matthew jones wrote:

> I really don't understand why people are so hooked up on using MIDI or
> serial/parallel ports for interfacing sensors with pd.  It strikes me that
> the absolute best way if you are at all worried about sample
> rate/quantisation amount is to use the audio signal inputs of your
> soundcard.  some simple circuitry and then you have maybe a 96kHz 24bit
> input - super fast control and with same latency!
> 
> am I mistaken? has anyone used this to good effect?  I was thinking that the
> terminatorX style turntable things are a prime example of where a mouse just
> doesn't offer enough resolution to do even a half decent job....
> 
> 
> matt
> 
> -=-=-=-=-=-=-=-=-=-=-=-=-
> http://www.loopit.org/
> -=-=-=-=-=-=-=-=-=-=-=-=-
> ----- Original Message -----
> From: "Marc Lavallée" <odradek at videotron.ca>
> To: <pd-list at iem.at>
> Sent: Friday, October 31, 2003 2:01 PM
> Subject: Re: [PD] Sensors
> 
> 
> > 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).
> > http://www.pure-data.org/Members/odradek/parapin
> > --
> > Marc
> >
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> >
> 
> 
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