Hey, Great project! Kinda new to this side of things (computer guy) so i have a few questions for you if you don't mind! been experimenting with this.
First, i couldn't find any of the peizo's you used in Canada (radioshack closed here) so I got some pizeo film tabs from http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=MSP1006-ND
Now, they do seem to be partially working but I'm having a lot of problems with sensitivity. I hit it once and it goes twice, or I don't hit it at all and it still registers as a hit.
The threshold doesn't really have much effect for me (inside arduino or ardumo.
Do you think this could be because I need to use a higher value resistor on the piezo? I'm using the 1m like yours and todbot.
I've tried a few differen't smooth functions with no luck. I have managed to get it to stop hitting on its own at points (by setting threshold/smoothing functions), but I can't get a consistant single hit from it when I give it a good wack, it likes doubling up on me.
Also, Its really hard to tell from your video because your child is playing, but how fast does it respond? not meanig the delay between the computer, but can it pick up doubles and midium speed rolls? Mine does not seem to be able to pick up anything above maybe 80 bpm, am I expecting too much from this? (I figured 57600 should be quick enough to send pretty fast signals but maybe I'm crazy?)
And when I look at the serial monitor (with your ardumo ardunio code) I'm seeing a constant sending between 0 - 400 (give or take, there are spikes) and when I hit it, it usally only registers in the 420-500 area, with some going up into the thousands for what appears to be no reason (doesn't match the strength I hit it at).
What kind of numbers do you get in your serial monitor, a) when nothing is happening and b) when you hit it, and when you do hit it do you get just one number or does your java program smooth it out? ( I get multiple readings per hit) I'm thinking my numbers must be varying a lot more then yours.
Last thing I can think of, does the piezo senor you use sense vibration as well? because I've been noticing feedback from me moving and such close to it.
I'm not really sure where to go next, my best guess would be something like http://www.musicfromouterspace.com/analogsynth/SOUNDLABMINISYNTH/drum_trigger.html
but your numbers from the serial output would deffently put me in the right direction.
Anyways, that sure was mouth full. Any help you can give would be awsome, love to get this going right!