A well functional e-drum trigger pad. It's still work in progress but I'm very happy with the results so far. I'm going to build a whole e-drum set around this, including a kick-trigger and cymbals. You can watch the progress on thingiverse and for most recent changes look on my git repository:
https://github.com/Piesi/pE-Drums.git

You are of course also well welcome to contribute!

Non printed parts:
-Threaded rod (6mm,130mm)
-4 M6 75mm bolts
-6 M6 25mm bolts
-1 M6 50mm bolt
-M6 nuts
-Sensor piezo (like this one http://en.wikipedia.org/wiki/File:Electronic_component_piezo.jpg)
-8" meshhead
-a jack socket.
-sponge or felt (between the sensor and the mesh, hope to find
a printable solution soon)

The printed parts of my version weight about 375g.

Print every part just one time, except the baseC and rim files. BaseC has to be printed 2, the rim 4 times. The biggest part, the shell, has a diameter of 180mm.
I have printed them with a 0.8mm nozzle, as for my experience this is the best choice for strong parts and fast results. Other print settings were 0.25mm layer height and 30% infill.

Cut the threaded rod in pieces:
4 * 230mm
2 * 190mm

The assembly can be figured out by the pictures, I hope. If you have problems, just ask:)