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Trigger input processing: no filter or level trim necessary?

PostPosted: Thu Mar 12, 2009 1:14 am
by stpope
Hi all,

I apologize if this has been hashed out in these forums (fora?) before, but in comparing the Megadrum analog board with the comparable designs (eDrum, Rich Heslip's, PAIA), I'm struck by its simplicity -- no buffer op-amp, level trim pot, or low-pass filter in the trigger signal before the analog mux. :o

Not having access to the source code of the code that the Atmel microcontroller's running, I'm confused/concerned. Do users have any issues with this, for example on sets with a mix of sensor brands or with DIY sensors?

I'm wondering whether I should try building an input board based on the eDrum's and testing it with the MegaDrum.

...any reply appreciated...

Stephen Pope

Re: Trigger input processing: no filter or level trim necessary?

PostPosted: Thu Mar 12, 2009 2:25 am
by dmitri
stpope wrote:I'm wondering whether I should try building an input board based on the eDrum's and testing it with the MegaDrum.

It will not work.

Re: Trigger input processing: no filter or level trim necessary?

PostPosted: Thu Mar 12, 2009 9:36 am
by Synthex
stpope wrote:Do users have any issues with this, for example on sets with a mix of sensor brands or with DIY sensors?

No. It works perfectly. :D

stpope wrote:I'm wondering whether I should try building an input board based on the eDrum's and testing it with the MegaDrum.

Why do this ? :shock:

eDrum analog can not support 3 zone cymbals (Yamaha style), Megadrum can
eDrum analog can not support the choke feature on each input, Megadrum can
...
...

Re: Trigger input processing: no filter or level trim necessary?

PostPosted: Thu Mar 12, 2009 3:52 pm
by elrules
Synthex wrote:eDrum analog can not support the shock feature on each input, Megadrum can..
By the way, what is the shock feature? :shock:

Re: Trigger input processing: no filter or level trim necessary?

PostPosted: Thu Mar 12, 2009 4:21 pm
by Synthex
elrules wrote:
Synthex wrote:eDrum analog can not support the shock feature on each input, Megadrum can..
By the way, what is the shock feature? :shock:

Yes, sorry, it's Choke. :?

CC Choke support on every Dual Zone piezo/switch pad or 3 zone cymbals.

Re: Trigger input processing: no filter or level trim necessary?

PostPosted: Thu Mar 12, 2009 4:53 pm
by Ken Forgettable
stpope wrote:-- no buffer op-amp, level trim pot, or low-pass filter in the trigger signal before the analog mux. :o

Don't be concerned see this: https://www.megadrum.info/~megadrum/forums/viewtopic.php?f=3&t=108&hilit=4851&sid=4e0a622f3432d1443e1e597b0e7699e4

and compare to this: http://www.electro-tech-online.com/micro-controllers/88275-using-adc-16f877a-measure-short-signals-piezo.html

stpope wrote: Do users have any issues with this, for example on sets with a mix of sensor brands or with DIY sensors?

... there has to be some give and take - we can do the confused bit ;¬\

Re: Trigger input processing: no filter or level trim necessary?

PostPosted: Fri Mar 13, 2009 1:43 am
by stpope
Thank you, fellows, for these explanations!

I'm just a bit disappointed there really isn't a shock feature... :lol:

stp

Re: Trigger input processing: no filter or level trim necessary?

PostPosted: Fri Mar 13, 2009 2:52 am
by jamalpiper
stpope wrote:Thank you, fellows, for these explanations!

I'm just a bit disappointed there really isn't a shock feature... :lol:

stp


You have to cross a few of the wrong wires to get that =P.