Internal Trigger v2
by PFozz
This internal trigger works nicely. It’s cheap and easy to build 😉
PARTS NEEDED
. Some kickboard foam
. 2 thick wood discs (must be non flexible)
. Crossmember material (must be non flexible)
. 2 screws
. Some double-sided tape
. 1 foam cone
. 1 piezo transducer
. 1 rubber seal ring (same diameter than the transducer)
SOME DETAILS
.One of the wood disc is optional, and is just here to hide the stuff inside (when looking under the shell). This disc (or whatever shape you use) should then be bigger than the other wood disc, and is attached under the cross member using 2 screws.
.The big piece of foam that I put between the upper disc and the crossmember isolates the piezo from the shell. It’s easy to add a rim trigger then, and at least, it will significantly reduce false triggering.
.The foam cone is made of foam taken from a kickboard, here. The foam cone is a critical part of this trigger. You may directly buy a Roland cone, but it’s interesting to experiment with various material. The foam from a kickboard may work for you (depending on its properties). The foam used to shape “puzzle mats” is good aswell. EVA foam seems to be excellent for such an application, too. If shaping a cone is a problem for you, just build a “ballistik trigger” (see the design by Michael Beatnik). Anyway, I have to think about writing a page dedicated to foam cones/cylinders/… someday 😉
.I’ve used double-sided tape to attach everything together (except the big wood disc). That’s why the rubber seal ring seems to be yellow on the following picture (it’s black, actually).



We’ll see later some ways to set the all thing in a shell.
Best!