[LAU] [OT] DIY Trigger - Piezo to MIDI to PC

Sorry for the very random subject, but I figured I'd need all the help I can get. I've read about this for a _little_ while (time constraints..arghhh) on the WWW, and I've posted on www.edrum.info too. In case anyone here has better/fast/helpful suggestions/advice/shizznit, I'm sort of cross-posting: I just want one trigger, which I'll use for the kick drum. As such, I'm interested to know if there are premade boards for the MIDI conversion. Basically all I need is something which can take the vibrations and convert them to electrical signals (piezo), and then fed to something else that will convert that electrical signal to a MIDI-ON message, after which I can plug it into the MIDI input of an audio interface or use a MIDI-USB adapter to plug in to a USB port. And regarding MIDI, if I want to take into consideration dynamics, and let the piezo trigger MIDI messages with varying attack information, how would it be done? So depending on the voltage generated, it'd be a MIDI-ON but the final message to the computer (audio interface) would be a "MIDI-ON && ATTACK == 75" sort of logic. Sorry for the noobish description, have just started to dabble into (audio/midi) electronics. I understand the concept and design roughly and I can move on by reading the construction manual (refering to edrum's DIY guide), but at the moment I'm looking for a quick way to build a trigger as I need it asap (and no $$ for a real trigger kit/module).