[PD] triggered oscilloscope/bang on zero crossing?

Derek Holzer derek at umatic.nl
Wed Dec 9 01:14:12 CET 2009

Hi Mike, Roman,

thanks for the input! Of course I thought it would be simpler, but I did 
keep in mind this block boundary problem. [edge~] is a good suggestion, 
at least that's the kind of object I was looking for. I'll have a look 
at your forum patch tomorrow Mike (assuming I can find my login for the 
forum). The block issue, well that's another story...


Mike Moser-Booth wrote:
> cyclone's [edge~] is useful for converting zero crossing to bangs:
> [inlet~]
> |
> [expr~ $v1<0]
> |
> [edge~]
> The only downside is that it quantizes to the end of the block, but then 
> again, so does [tabwrite~]. I actually attempted doing one with edge and 
> posted it on the forum, if you're interested.
> http://puredata.hurleur.com/viewtopic.php?pid=14984#p14984
> .mmb
> Derek Holzer wrote:
>> I'm trying to put together a simple oscilloscope abstraction that 
>> imitates the "trigger" function of a real one, so that the waveform 
>> can be seen from its starting point.  In other words, a [tabwrite~] 
>> would graph on the upward swing of a zero crossing. To do this, I'd 
>> like to know if there is an audio object which gives a bang at a zero 
>> crossing, or perhaps even only at a crossing from the negative to the 
>> positive domain of the signal. I've thought of something with [expr~ 
>> $v1 < 0], but what comes out is still in the audio domain and isn't 
>> the bang which [tabwrite~] needs.
>> Other suggestions welcome.
>> best!
>> Derek

::: derek holzer ::: http://blog.myspace.com/macumbista ::: 
http://www.vimeo.com/macumbista :::
---Oblique Strategy # 101:
"It is simply a matter of work"

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