[PD] Piezo, trigger, Arduino

Tee pd at dadacafe.org
Wed Jun 22 21:16:39 CEST 2011

Hello, (some time lurker, first post)

On 17/06/2011 14:27, Pierre Massat wrote:
> Dear List,
> This is yet another question about Arduino. Sorry about that.
> I want to use piezos to trigger samples using my arduino board. I want the
> trigger to be sensitive, and a quick google search seems to show that piezo
> is the way to go.
> Does anybody have any experience with piezo triggers (what type of piezo,
> isolating each piezo, etc.)? I will hit the piezos with my bare fingers (no
> drumsticks or anything like that), but i guess it doesn't really matter
> since i can control the threshold within Pd.
> This last sentence is just to make sure that everyone knows i'm talking
> about piezos in case there wasn't enough occurences of the word in my
> message.
> Cheers!
> Pierre

i am currently building something similar, but triggering synthesis
instead of samples.
While i can't really comment on my piezos (i had them for a long time
until i put them to use), an oscillograph showed they have their biggest
peaks between 8.88 and 9ms.
The arduinos analogue inputs give values between 0 and 1023 (10 10bits).
Using the piezos with or without their shell makes a huge difference in
the values propagated to pd.
i asked someone more knowledgeable than me about a circuit with the same
purpose (just reading the "biggest amplitude" of the piezos response)
using <http://www.workinprogress.ca/projects/edubeat/source/> but he
replied that this specific one would mostly show the characteristics of
the capacitor and recommended using a Schmitt-Trigger instead.
I'm documenting my project on
<http://forkbomb.dadacafe.org/blog/ardrum/>, it is still a work in
progress so not everything is up there yet.



More information about the Pd-list mailing list