Well, it had to happen. I broke my kick pedal again the other day. I had a bit of a hard time fixing it up (more on that later), so I figured I'd go all-out and build a real kick pedal controller for my Guitar Hero: World Tour drumset (like the ones you can buy on various sites).
If there's one thing I appreciate about the Rock Band / Guitar Hero instruments, it's that they're very simple. The drums, for example, are simply piezoelectric vibration sensors that you can attach to pretty much anything you like, such as a tabletop, a real drum kit, a book, or anything else you can think of. Piezo sensors create DC output when they vibrate, so basically, the drum controller uses this electric signal to tell when you've hit something, and also how hard you hit it. This is why an overly sensitive drum head sometimes experiences 'crosstalk', because the sensor is picking up vibrations that it's not supposed to (or it's badly soldered onto the wire and coming loose).
The GH:WT kick pedal also has a piezo sensor, contrary to the Rock Band 1 pedal, which uses a magnetic switch. Both are about as simple, however: each one uses two wires connected to a mono audio connector like the ones you can buy in electronics stores. This makes it really easy to create a functional replacement pedal (it doesn't even have to be a pedal at all).
I went to a local music store and bought a cheap, run-of-the-mill chain-driven kick pedal. I was talking to the guy behind the counter when he mentioned he had a drum practice pad with a broken sensor inside of it. Since the sensor he was talking about is for real electronic drums, I took the pad off of his hands.
The pad looked pretty cool, since it had a socket for a 5/16" bolt on the back. I figured it would fit nicely on a metal pole, especially if I could find one that was pre-drilled with holes. At my local hardware store, all they had were solid lengths of steel pipe. I'm not equipped to drill holes in pipes, and they couldn't do it on request either, but I brought a suitable length home anyway, thinking it was at least good enough for a prototype.
My friend Bob, plastic guitarist extraordinaire, has participated in my fake instrument mods since we started playing Guitar Hero a short while ago. I enlisted him to give me a hand in creating a suitable base for my new practice pad. This monstrosity is what we came up with:
Yes, those are tie-wraps. We used a whole bunch in this prototype, mostly because we're lazy, and we like cheap things that do a great job. It's easier than drilling holes through steel pipe, at any rate.
contact microphone, and you can test it by plugging it into a set of speakers, putting the sensor against a surface, and then tapping on the surface. You should hear a kind of scratchy thump if it's wired correctly. There's not much else to it: if you've soldered the wires to both ends correctly, it'll work, nothing else is needed. As you can see, this one has been used a few times, but these kinds of sensors are pretty tough and the extra bits of solder don't do any harm.
In order to protect the sensor, we wrapped it tightly in electrical tape. The solder could get shaken loose if you leave it exposed, especially if you have a tendency to be rough. You'll also want to make sure the wires aren't exposed. This is what the finished sensor and cable looks like.
Once the piezo sensor was wired up, we glued the sensor to the inside of the practice pad, as this image shows. We used some quick-set epoxy, which is a pretty resistant glue that bonds almost anything. We also taped the wire down in a few places in order to avoid having any extra hits being created by the wire moving around. Adding some sort of soft foam on top of the sensor in order to contact the practice pad's drum skin might enhance the sensitivity, but we didn't have any lying around, so we saved that option for the updated version.
We reassembled the pad and strapped it securely to the length of pipe I bought.
So far, so good. Bob went to work, creating a suitable wooden base that allows us to drop the steel pipe in and attach the pedal. We had something much more ambitious at first, but Bob's love of tie-wraps took over, and we ended up with this:
Okay, so it looks a bit weird. The question is: how does it perform? I've only tested it once, but so far, it's been great! Double and triple kicks have never been easier, it hardly makes a noise, and every bass hit is accompanied by a solid thumping sensation, which is way more interesting than playing on a plastic pedal.
The great thing about this kind of mod is that once you've wired that piezo sensor up, you can connect it to almost anything you can tap, whether it's with a drum stick, your hands, feet, or anything else.