I'm trying to build an electric xylophone. I want it to be pressure/velocity sensitive so I decided to use piezo-elements to pick up 'hits'. Below is a close-up picture of my setup. So every bar you see (4 total) has a piezo-element taped onto the bottom. The bars are attached to the foam with CA glue/superglue and the foam is in turn glued with CA glue to the wooden piece beneath it.
When I hit a bar (hard enough to exceed a certain threshold), the piezo is read on an arduino which finds the peak in the signal and converts it to MIDI, that is in turn send to a Raspberry Pi which produces a tone. The idea of the blue foam, is that when I hit one bar, other bars (piezos) will not vibrate enough to produce a tone.
However, the problem I'm facing is that the blue foam is currently not dampening the vibrations enough. When I hit a bar not even all that hard, it will already trigger other bars as well. A side-problem is that I don't need to hit very hard to make the piezo send out its max value (5V). That relation could perhaps be solved if I would have less sensitive piezo-elements. Do those exist? The first (main) problem is more urgent to me though. So do you have any ideas on how to dampen the vibrations better to prevent other bars from vibrating as well?
Here is a picture of my electronics to some extent. The piezos are to the right of the picture, they are inserted in the blue breadboard, each with a 1 Mohm resistor. The inputs are then wired to the transparent breadboard where they are connected to a mux (CD4051BE). The mux is connected to an arduino analog input (most left yellow wire). This setup is because I eventually want to connect 16 piezos to 1 arduino.