Looks like the first pad is going to be the kick drum because I've misjudged the whole deal. I went to Ace Hardware today and picked up the stuff. I pretty much just guessed on everything. I bought:
- Five 5/16" Bolts, Approx 3" long @ 0.19 ea\
- Seven 5/16" Nuts @ 0.07 ea
- Four Springs @ 0.79 ea
- Seven 5/16" Terminal Rings @ 2.49 total
I guessed well on the length of the bolts, the nuts obviously aren't a guess, neither are the terminal rings. The springs, however, were not a good guess. It's surprising how much different a spring feels in your hande versus mounted. The ones I picked are way to stiff, but I think they'll be okay on the kick, because the beater hits a lot harder. Plus I won't need to put padding on it to dampen the sound since the beater is some soft material anyways.
The other change in the design I'm making is to get some bolts with flat, threadless areas up at the top of them, about an inch worth. When the top board is pushed down it can catch the threads on it's return, so that's kinda iffy.
I also did some browsing today. See, I never actually did any poking around on the net before starting, I just got the idea and started building. It seems that DIY triggers aren't that hard to find. Most are made of a piezo tansducers and practice pads. Example. I haven't the slightest if that would work here. I think those are more of a range of current, as opposed to a strict on/off like a keyboard. I fully intend to go buy one after work tommorow and meter it to see if it can handle the job. That would make life much simpler. If not I can just make it into an acoustic guitar pickup.
Here are the required photo's. The little white box is the home from the keyboard circuit board plus my little "breakout" board. I made that because I couldn't solder directly onto the contacts, so all the connections are hot-glued and the breakout board is to reduce the amount of wiggling and tugging I do on the board to finish it up.