I mostly built this to see if it works. Since then, I’ve noticed that quite a few other people around the internet have had similar ideas and/or knew about this prior to myself, but that won’t stop me from presenting my totally original and uninformed take.
A while ago, one of the drum pads on the Roland kit at Church (we have the 8″ round black rubber ones, not the V-drum type) wasn’t working very well. It turned out to be a bad solder joint on the jack but while I had it apart I noticed that all that’s in there is a 1/4″ mono jack, two wires and a piezo element (one of the bigger 1.5″ or so ones). “Hey, cool,” I thought, “I’ve got a couple smaller piezo elements sitting around from electronic toys and stuff. I bet I could build one of these things.” Of course, It took me long enough to get around to it, but who cares, it mostly works.
A little (very simplified) background: if you know this stuff, skip it. A peizo element is a thin layer of a special crystal sandwiched between two pieces of metal. If you apply a voltage to it, it vibrates (with a couple caveats), and if you vibrate it, it generates a voltage. Pretty cool. You can find one in the back of your watch or in almost any electronic toy that makes beeping noises. Don’t take the one out of your watch, though – they are a _royal pain_ to solder leads to, so I gave up after about ten or fifteen minutes and used one that already had wires on it.
Below is a pic of the bottom of the finished product, showing piezo element, wiring, and the special Hasbrouck High-Tech Mounting Device. The piezo element is held on with a couple daubs of Shoe Goo ™ around the edge.
More simplicity. The rubber sheets on the top are bicycle inner tube (great stuff) just so you don’t get as much of an audible click when you hit it. I Glued it on with contact cement.
The hunk of aluminum I glued everything to is the top off an old Seagate hard drive, but anything rigid enough to stand up to a drummer pounding on it will work – just so it’s hard enough to conduct vibration, too.
Now the Crucial stuff: mounting hardware. Easy and cheap – a 1″ or so 8/32 bolt, wing nut, fender washer, two hunks of 1/4″ thick rubber from a 4″ rubber pipe cap, and a 3/4″ PVC pipe cap. The rubber and pipe cap I had around from the watergun project.
Side View. Shows a little bit of mounting construction. The wire tie hangs on to the jack pretty well – I just had to drill another hole for it to go through.
Simple on the other end, too, as you can see. One 1 3/4″ to 2.5″ (approximately) hose clamp, and a 5″ piece of 3/4″ PVC. It tends to wiggle a bit, though, two clamps and a longer piece of pipe would really be better.
Makes a pretty decent wood block or cowbell…It doesn’t quite have the same sound as a real Roland trigger, but that may be due to the Piezo element size. The real triggers use one that’s 1.5 in. or so, but I didn’t have one that large. Good proof of concept, anyway.