[PD] jittering sensors

[Hans-Christoph Steiner]

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
>
>
>
> _______________________________________________
> PD-list at iem.at mailing list
> UNSUBSCRIBE and account-management -> http://lists.puredata.info/ 
> listinfo/pd-list