Positional Sensing / Zone Detection - a little story...

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Positional Sensing / Zone Detection - a little story...

Postby fankelomia » Tue May 09, 2017 11:30 am

Hello all,

i was thinking about positional sensing, or maybe better termed zone detection, without the need for a center-cone-trigger or a side-mounted trigger in combination with a (non-piezo'ed) center-cone/stressball/etc.

I am guessing we all are at one point or another :lol:

To try something out, i just taped two piezos to the underside of a meshhead (drum-tec pro, which is why i also stuffed the drum with a fleeceblanket) - one piezo at the utmost edge and one in the center.
I wired them like you would normally wire a head/rim-piezo pad. This actually worked quite well and not even the crosstalk was an issue, since hitting head and rim under normal circumstances would create a rimshot in this case it just created a head or half edge sound (depending on which note i selected).
Of course it worked best/only in the quarter to half part of the drum into which i placed the edge-piezo.

So using the tweakability of Head/Rimshot/Rim triggering, one can actually achieve some form of zone detection. Maybe that's not actually news, for me it was.

But of course the downside comes when actual Rim/Rimshot triggering is added.
Since the spot on the mesh-head which i usually strike when doing rimshots lies in the zone i was using to only play the head-sound and not the half-edge-sound, i wired the center-head-piezo (additionally to the existing wiring) and a rim-piezo like a normal dual-pad and plugged that into a second input.
Configuration wise this would also go like a normal dual-pad except that the head-piezo would not be used to actually trigger a sound, only to decide wether the rim was hit alone (rim click) or together with the head (rimshot).

Pretty sure you guessed it, because of the wiring of the center-head-piezo in the first input i would get a rimshot only accompanied by a normal head-sound. Soundwise not the worst, but looking at BFDs/Mainstages Midi Log it was either one or the other that was received first which could result in some timing discrepancies.
This also means that the possibility of loading a second instance of BFD and for example choking the snare with the head-sound in one instance when playing the rimshot of the same snare in the second instance is there but not consistent in what will come first.

But none the less building a drum with one reflection plate for head- and another for half-edge-triggering (maybe a "circle" on the lower and something like "half-a-circle" on the upper part of the head where one would be more likely to play the half-edge-sound...).

Any ideas how to get rid of the "double-sounding" center-head-piezo?
Having the rim-piezo control a relais which disconnects the wiring to the first input :shock: ?
Implementing something like a two-step-midpoint/width calculation inside megadrum for three piezos :oops: ?
Or using something like an arduino to take the input of all three piezos, see which one was struck how hard and then give out those exact values to the corresponding inputs of megadrum :roll: ?

Very happy to hear your thoughts!!
fankelomia
 
Posts: 10
Joined: Fri Apr 10, 2009 6:43 pm

Re: Positional Sensing / Zone Detection - a little story...

Postby fankelomia » Tue May 09, 2017 2:45 pm

I thought about it a little more and since i won't rely on the results i got so far i build the following construct in my head, unfortunately i won't have time to build it (properly) for real in the near future:

For demonstration purposes i will theoretically build a snare drum with two zones on the head, divided in the middle and a third zone on the rim.

For the head-zones imagine a reflection plate trigger with the reflection plate cut in half and a piezo on each (upper and lower) half and the rim piezo however one likes. The upper half would be for Edge-Sounds, the lower half for Hit-Sounds.

Now the wiring would be (all three Inputs as "normal" piezo/piezo-pad-inputs):

Input 1 "Head" = Rim Piezo
Input 1 "Rim" = Upper Piezo + Lower Piezo

Input 2 "Head" = Lower Piezo
Input 2 "Rim" = Rim Piezo + Upper Piezo

Input 3 "Head" = Upper Piezo
Input 3 "Rim" = Rim Piezo + Lower Piezo

And the sound/midi-note assignment - their activation would now depend on the setting one would normally use to distinguish between Head/Rim/Rimshot:

Input 1 "Head" = Rim-Sound (as long as Signal on Input 1 "Rim" is low enough)
Input 1 "Rim" = none
Input 1 "Rimshot" = Rimshot-Sound

Input 2 "Head" = Hit-Sound (as long as Signal on Input 2 "Rim" is low enough)
Input 2 "Rim" = none
Input 2 "Rimshot" = none (or to a certain degree also the Hit-Sound)

Input 3 "Head" = Edge-Sound (as long as Signal on Input 3 "Rim" is low enough)
Input 3 "Rim" = none
Input 3 "Rimshot" = none (or to a certain degree also the Edge-Sound)

This constellation could (theoretically) be able to shift the midi-note-output according to whichever zone was played while taking into account the crosstalk issues between at the very least the two head-piezos.

It might also result in a very complicated drum which will never output anything... :lol:

It wouldn't be the first time i was completely wrong, maybe someone can tell me so before i start building it... :D
fankelomia
 
Posts: 10
Joined: Fri Apr 10, 2009 6:43 pm


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