Positional sensing testing

Discussions related to MegaDrum Hardware

Re: Positional sensing testing

Postby dmitri » Sun May 09, 2010 2:43 pm

It's just as Ken said, at the moment it is just either a peak detection or a zero/threshold crossing detection.
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Re: Positional sensing testing

Postby Trommeltotti » Sun May 09, 2010 7:35 pm

dmitri wrote:Most of the branded mesh pads out there, like Roland, Drumtec and etc, produce a negative first half wave.


Your are right!

@Dmitri: I like to submit you a proposal:

It is time to "piss of" the impertinent old and expensive ROLAND modules with bad sounds far away from here to the moon and using modern VST drum sounds like Toontrack! But we all need a alternative well working triggering solution for this! And please without any extra soldering jobs like "voltage dividers" and "full wave precision rectifiers" and so on!

Let me explain:

To play E-drums with a close A-drums feel it is in my opinion compelling necessary to use modern full drum shells with stereo dual center triggering cones and a rim trigger with 2-ply meshes! Like the E-drums pads from drumtec and Diamond Electronic Drums are do.

But sorry for this: The MegaDrum converter is right now not able to use those mesh drums with an optimum as maybe possible. For example: ROLAND modules are not allowing to play a real dual stereo hit on the drum with a stick!!! In real conditions a "rimshot" hit sound generates when you hit both head and rim points at the same time! But ROLAND modules suppress artificially those playing technique and the MegaDrum module does not! Because when you use very sensitive preferences for the Head trigger for extremely detailed performances you automate got trouble to use the rim trigger without getting false and crossover signals from the close head trigger! Remember please that the analogue piezo triggering system is very simple and certainly not optimal for using to drummers!

So what does ROLAND do: They cheat simple!!! It doesn't matter if you hit really both areas (head/rim) at the same time you will just hear one sound! (remember a real "rimshot" sound generates only with hitting both areas at the same time) The MegaDrum could do this but with above described problems.

For the future there must be come a completely new triggering technique without piezos with a direct communication from drumstick to the hit area on the completely drum set and cymbals. I don't know how it should works but this is far away to the future.

So what can we do?

My idea is that this community collect an extra donation for each person for about 5-7 EUROS for @dmitri and from this money @dmitri is buying - I would say a reference dual stereo 14" mesh snare - from drumtec (diabolo) so that @dmitri is hopefully able to optimize the MegaDrum module for those reference drums with all features like postional sensing to get the best results with mesh drum systems without using ROLAND modules.

@Dmitri what do you think about this?

Greats

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Re: Positional sensing testing

Postby mackanov » Mon May 10, 2010 1:30 am

The 20100509 firmware fails to boot on my build (644-20-32).
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Re: Positional sensing testing

Postby zaklinacz » Mon May 10, 2010 5:17 am

Hi,
on my config 32-16-32 it also fails.
Contrast control is not working, under the light I can see very bright welcome screen, but nothing can do with keyboard.
BR
Michal
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Re: Positional sensing testing

Postby dmitri » Mon May 10, 2010 9:55 am

Trommeltotti wrote:@Dmitri what do you think about this?

First of all, as it is I'm always working on improving MegaDrum both software and hardware wise.
Second, on quite a narrow users base type of projects, like MegaDrum is, donations have very small impact. Don't take me wrong, I'm very grateful for all the donations but they are very rare.
Third, I wouldn't be comfortable taking donations for some future features without guarantee being able to deliver them.
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Re: Positional sensing testing

Postby dmitri » Mon May 10, 2010 9:56 am

mackanov wrote:The 20100509 firmware fails to boot on my build (644-20-32).

Oops, I will post another firmware tonight.
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Re: Positional sensing testing

Postby dmitri » Mon May 10, 2010 5:39 pm

dmitri wrote:
mackanov wrote:The 20100509 firmware fails to boot on my build (644-20-32).

Oops, I will post another firmware tonight.

I've updated the first post with new firmware.
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Re: Positional sensing testing

Postby dmitri » Tue May 11, 2010 11:42 pm

Updated the first post to include a schematic of a precision rectifier required for pads such as Roland-PD125X, Drumtec.
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Re: Positional sensing testing

Postby zaklinacz » Wed May 12, 2010 5:30 am

Hi Dmitri, one question about rectifier:
It is only for head piezo? Because then in eg. Roland pad we will have also "positive" rim. Will this work?
Because everywhere I've looked the rim and head piezos are connected in opposite.
EDIT: ok, the answer is below, only in Roland type pads they are in opposite (head negative, rim positive).
BR
Michal
Last edited by zaklinacz on Wed May 12, 2010 6:46 am, edited 1 time in total.
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Re: Positional sensing testing

Postby rockdude » Wed May 12, 2010 6:39 am

Just want to check if I understand this correctly. If my pad is wired like this, the first half wave of the signal will be positive and I won't need a precision rectifier?:
Image

I read somewhere that the "Roland way" of wiring improves the positional sensing accuracy. I wonder why a negative first half wave is preferable over a negative first half wave? Maybe it's just module specific for Roland?
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