[PD] jittering sensors

Hans-Christoph Steiner hans at eds.org
Fri Aug 18 05:59:31 CEST 2006


You can easily do that with the right-shift operator [>>].  But I  
think there are better techniques to achieve a cleaner signal.

.hc


On Aug 15, 2006, at 10:27 PM, dafydd hughes wrote:

> sorry hc - hit the wrong button.
>
> On 8/15/06, dafydd hughes <dafydd at sideshowmedia.ca> wrote:
>> Is it possible to chop off the smallest bit or two of the sensor
>> output i.e. reduce the resolution?  I remember using a basic stamp
>> program that did that for midi data.
>>
>> On 8/15/06, Hans-Christoph Steiner <hans at eds.org> wrote:
>> >
>> > On Aug 15, 2006, at 7:54 PM, Cesare Marilungo wrote:
>> >
>> > > derek holzer wrote:
>> > >
>> > >> If all the IRQ stuff that was just suggested doesn't make you
>> > >> happy, try this:
>> > >>
>> > >> [sensor input]
>> > >> |
>> > >> [pack 0 n]     (where 'n' = the time in miliseconds you would  
>> like
>> > >> your signal smoothed by)
>> > >> |
>> > >> [line]     (or [line~] if you are using it to control an audio
>> > >> signal]
>> > >> |
>> > >> [expr x]  (where 'x' is some math to get the numbers where you
>> > >> need them)
>> > >> |
>> > >> [whatever happens next]
>> > >
>> > > This adds latency and results are still (albeit less) jumpy.
>> > >
>> > > To smooth out a signal coming from a control (especially for midi
>> > > ctls)
>> > > i use:
>> > >
>> > > [input]
>> > > |
>> > > [sig~]
>> > > |
>> > > [lop~ n]         (try a n value between 20 and 50)
>> > > |
>> > > [whatever]
>> > >
>> > > Found the trick above posted on this list by somebody else.
>> >
>> >
>> > You can also achieve this without the added load of audio objects.
>> > [iir] and [lop] in mapping provide filters in the message domain.
>> >
>> > .hc
>> >
>> >
>> >
>> >
>> >
>> >
>> > >
>> > > c.
>> > >
>> > >>
>> > >> You could also explore [pow] or some of the other maths to do  
>> the
>> > >> job of [expr] if you aren't a math whiz. The [line] object is
>> > >> really handy to smooth out a jumpy signal. Try different  
>> values of
>> > >> interpolation (i.e. the 'n' in the [pack] object), depending on
>> > >> how fast you need a response versus how jumpy the input is.  
>> There
>> > >> used to be a [speedlim] object that also did this nicely and was
>> > >> really designed for sensor input, but the maintainer (Johannes
>> > >> Taelmann) doesn't seem to be maintaining it (and has dropped off
>> > >> the face of the Earth as far as PD in concerned unfortunately!).
>> > >>
>> > >> d.
>> > >>
>> > >>
>> > >> David Powers wrote:
>> > >>
>> > >>> Maybe I don't know what I'm talking about, but couldn't you  
>> just
>> > >>> take the average value over some time period?
>> > >>>
>> > >>> ~David
>> > >>>
>> > >>> On 8/15/06, *patrick* < patrick at 11h11.com
>> > >>> <mailto:patrick at 11h11.com>> wrote:
>> > >>>
>> > >>>     hi all,
>> > >>>
>> > >>>     i've done a project using the MULTIO of mamalala and HID to
>> > >>> capture the
>> > >>>     output of my sensors (infra-red, tilt and such). sadly the
>> > >>> values are
>> > >>>     really jittering and i have a logarithm sensor too.
>> > >>>
>> > >>>     i know that each case is unique, but maybe there's some  
>> rules to
>> > >>>     stabilize the fluctuation and correct the curve  
>> (logarithm)???
>> > >>>
>> > >>>     thanks for sharing any knowledge on this!
>> > >>>     pat
>> > >>
>> > >>
>> > >
>> > >
>> > > --
>> > > www.cesaremarilungo.com
>> > >
>> > > On the Internet, no one knows you're using Windows NT
>> > >        -- Submitted by Ramiro Estrugo, restrugo at fateware.com
>> > >
>> > >
>> > >
>> > > _______________________________________________
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>> >
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>>
>>
>> --
>> www.sideshowmedia.ca
>> skype: chickeninthegrass
>> www.myspace.com/dafyddhughes
>> www.myspace.com/thedeborahs
>>
>
>
> -- 
> www.sideshowmedia.ca
> skype: chickeninthegrass
> www.myspace.com/dafyddhughes
> www.myspace.com/thedeborahs
>
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