V.Sensitive Drum Buttons (MPC)

[Jidis]

Did anyone ever find any definitive info on doing these? I've read a few threads here on them, but they are more about integrating triggers into the "brain" part of the system. I'm looking for info on construction of the pads themselves (not external pads).

I've got a rubber supplier here, and already have a bunch of scrap rubber and new raw piezo elements, but don't know what the best way to construct a board would be for minimal crosstalk and accurate sensitivity. I've seen the inside of my PAD-80 and an SR-16. The pad 80 has rubber glued to individual metal plates, isolated by a rubber gasket frame thing. It also has additional triggers on the housing module, which may be preventing false triggers or something (this is for drumstick use). I don't guess I need anything that complex. The SR-16 has regular cheap rubber contact switches with maybe 3 piezos on the underside of the board that may be detecting overall velocity and applying it to each button input. I'll probably be using one trigger per pad.

I've got four different trigger to MIDI devices here to test with, so I may just start trying different stuff, but I don't want to repeat any experiments that 50 other people have already done ;) 

Please let me know here if you've got any good info or sites.

                              - Thanks!

George

[Davo]

Consider building an analogue to an electric guitar.  Recall how pickup coils work.  Now, here's my drum idea:

Start with a ring of tough plastic or graphite.  Put a layer or two of  leather on top.  Now wind a flat coil the same diameter as the drum and put it on the leather.  Glue a thin piece of steel to the center of the leather.  Add one or two more layers of leather.  Top with another ring of tough nonmetallic material.  Clamp this sandwich together real tight with nylon bolts and nuts.  Striking this drum will cause the steel slug to vibrate within the coil.  The induced currents are then run through amplifiers, filters, and other synthy gizmos.  Unlike typical on-off electronic drums, this thing will probably make a noise no matter where you hit it.

I cooked this up over a long drive today.  I haven't built any of this, but I just thought I'd throw it out for someone else to play with.

[1] I'm thinking vegetable-tanned leather (the stiff sort that pictures can be carved into).  Rawhide might be better.  I don't know for sure.

[Jidis]

Davo,

That does sound interesting, but maybe more for drumpad use. I think I'll get the sensitivity I need from straight piezos, but I'm wondering about the "housing" and attachment to the substrates/rubber, etc.

I also forgot to ask- The raw piezos I got are unwired, so if anyone knows of some good info on that part, I'd appreciate that as well. Specifically, the soldering of the wires to the discs and whatever glue would be best to secure the wires afterward, to attach the discs to the plates or whatever and to seal and protect the whole mess. I have to re-trigger some Simmons pads that I've been neglecting for a while as well, so they'll need some good reinforcement. From what I remember, they failed in that same area, but they are subject to much more abuse.

                          -Take Care 

[Davo]

So, you just want discrete triggering?

Now for soldering and glues:  I've never soldered piezo discs before, but I understand it's similar to soldering unwires solar cells.  In that case,  it's best to use paste flux.  Brush some on the device where you want the wire.  Put the wire in place and heat with your iron.  Make sure the iron has a somewhat heavy load of solder so it wets both the wire and the piezo.  Apply more solder if necessary.

Epoxy sounds like an ideal choice for gluing the piezos.

[JR]

Hi George,

i think you are searching for http://edrum.for.free.fr/  ;).

JR