Position sensing with FSR on a mesh head

[adrumsolo4u]

I have plans for a cheap mesh head, and i am adding a FSR (force sensitive resistor) for position sensing purposes to the mesh. I will be using a single piezo for sensing force as well.

I have never messed around with position sensing before, so i don't know yet the particulars, such as when a stick hits the head, how are the piezo's wired and what is the range of voltages that travel to the trigger module? I would rather not start this research from scratch when i know more than a few people know how this all works. My other question is how does the trigger module "read" this signal from the trigger?

I'm very familiar with electronic signals (i work on Comm/Nav systems on planes) but have never delved into the world of e-drums.

If this quesion has been asked or answered before, i apologize. In my defense i have been looking for quite a long time.

Edit: BTW i do understand how a single piezo works, but i'm not sure how the combination of 3 piezo's can be interpretted by the trigger module.

[Sylv1co]

Hi,
To be honest, I can't really imagine how a FSR can help regarding position sensing. As its name says, a FSR react to the force, not to the position.
Also, position sensing is allready implemented into Megadrum using only the head piezo signal, so why want you try to make it work another way ?

Edit: BTW i do understand how a single piezo works, but i'm not sure how the combination of 3 piezo's can be interpretted by the trigger module.

I don't know any module that uses a combination of three piezo. You can use two piezos on one drum, then the module compare the two signals and trigger a note only for the highest of both. A three zone cymbal uses one piezo (for the bow) and two swtiches (for bell and edge) or 2 piezos (bow bell) and one switch (edge). In both cases, if a switch is activated, velocity is determined by the piezo signal.

Three piezos may be used with the crosstalk feature, but then you need to get really good physical isolation between the three piezos, and that's very difficult on the same pad.

[Chrisk23]

I don't know any module that uses a combination of three piezo. You can use two piezos on one drum, then the module compare the two signals and trigger a note only for the highest of both. A three zone cymbal uses one piezo (for the bow) and two swtiches (for bell and edge) or 2 piezos (bow bell) and one switch (edge). In both cases, if a switch is activated, velocity is determined by the piezo signal.

Three piezos may be used with the crosstalk feature, but then you need to get really good physical isolation between the three piezos, and that's very difficult on the same pad.

Right, as far as I understand it, megadrum calculates the position by analyzing the signal from a single piezo. So if you want to improve it, build a precision rectifier instead (dmitri posted the schematics here in the forum).

[adrumsolo4u]

Right, as far as I understand it, megadrum calculates the position by analyzing the signal from a single piezo. So if you want to improve it, build a precision rectifier instead (dmitri posted the schematics here in the forum).

As I'm building a new trigger pad I'm hoping to improve upon current technology. There are two wayd i was thinking to go about this... but after you said that i think the only way i can do it is with two signals. One for the piezo and the other for position.

Does anyone know if dmitri has posted his MegaDrum firmware so that i can play around with it when i build the new pad? (un-compiled version of course)