Articles » Hardware Hacking for a Better Wii Zapper
If your tastes are like mine - and they should be - then you're probably disappointed that the Wii Zapper has a button layout woefully incompatible with "Resident Evil 4". RE4 uses the A button for "fire" and the B trigger-button for "draw weapon". The Zapper simply has a mechanical trigger that pushes the remote's B button. Most of the other third-party Wii gun attachments, including the cool-looking Nyko PerfectShot work the same way. (The exception is the Wii Blaster, which is even crazier and still doesn't solve the problem.)
So, since both Nintendo and the major third-parties failed me, I decided that the only option left was for me to make my own gun. I give you:
THE RESIDENT EVIL 4 WII GUN
The first step was to go down to Toys'R'Us and pick out a suitable toy gun. My main requirement was that the gun needed to already have an electrical switch in it, which ruled out all offerings from Nerf. I was actually surprised at the lack of selection, besides the Nerf aisle there were more toy swords than toy guns. I settled on the "Mars Assault Laser Blaster". It's an electronic noise-making thing with a couple of completely bogus attachments. (Like a scope you can't actually see through.)
This toy gun does not look particularly bad-ass, but it fit my needs because not only was it bulky enough to hold the guts of a Wii remote, it has a trigger, six extra buttons, and a speaker. It also had a bunch of bright blue LEDs which were salvaged and tossed in my junk box.
The gun was held together by a handful of phillips-head screws. All of the guts of the gun were conveniently on one side, and the only linkage between the two halves was the two wires leading from the battery compartment to the circuit board.
The gun's circuit board was held onto the shell with a few small screws and was also easily removed. It had a lot of wires running into it that could all be cut right off.
Once the gun was thoroughly disassembled and gutted it was time to move onto the Wii Remote. Wii Remotes are pretty easy to take apart if you have a goofy Tri-Wing screwdriver, but having the screwdriver isn't enough, you have to actually be able to find it for those two times a year you need it. This small detail held up the whole project for a week while I ordered a new one.
Surprisingly the Wii Remote's speaker isn't even soldered down. It just has two spring contacts pressing against the circuit board. This was a lucky break because my pansy "Cold Heat" soldering iron has trouble removing the newfangled lead-free solder which I think these things are held-together with.
After some investigation with a multi-meter, I determined that the buttons on the Wii Remote all share a common ground. Here is a rough diagram of the layout. Negative indicates the ground.
(Notice that I'm uncertain about left and right on the d-pad. I may have screwed that up. Also notice that there may be more than one model of Wii remote. This was a launch Wii remote.)
After determining the layout, the hard work began. Wires were soldered onto the + side of every button I cared about, and one wire was soldered onto one of the grounds. I used a ground from the B button, but the one from the A button probably would have been easier. The small flat buttons that make up the plus, minus, home, and power buttons were difficult to remove, so I didn't bother and just tried to solder to the corner of the existing button. This was a mistake as you'll see below.
The creators of the gun's circuit board were kind enough to add some points I could solder to. I'm pretty sure they were left there for testing purposes and are probably not ideal for soldering, but they work. Before I started adding my wires I used a box cutter to scratch through all the leads going from the button into the chip at the point right before they enter the chip. I don't want any current running through the gun's silly noise-making chip.
I could have run the wires right from the gun board to the Wii remote board, but for cable-management and trouble-shooting reasons, I decided it'd be easier to run everything through a small breadboard, cut in half to make even smaller. Because the pads on the gun board were so weak. and because my soldering skills are not the best in the world, I used electrical tape to hold down the wires I'd already soldered and stop them from pulling out of their joint. This had the irritating effect of obscuring which wire was connected to which pad and making me wish I'd used different colored wires.
Once the gun's buttons were connected to the breadboard I simply took the wires I'd connected to the Wii remote board and connected those to the breadboard. Since I didn't have enough buttons for all functions, I decided to abandon the directional pad, since it's not critical for RE4 (and, in fact, is rarely critical for most Wii games). I wrapped all those wires up and stored them in a nook in the gun casing, maybe they'll be used in future upgrades.
The gun's trigger was a very simple mechanism involving a wire that pushes into a small plate when the trigger is pulled, it was easy to solder a couple of wires to those contacts. A button I got at RadioShack became the "Draw Weapon" button. Both the button and the trigger were connected to a switch so that I can swap their functions effectively giving me an "RE4 Mode" and a "Link's Crossbow Training Mode".
After the bulk of the soldering was done I turned my attention to the gun case itself. The most substantial modification to the case was in the battery compartment. The gun took three AA batteries, but the Wii remote only needs two, so some changes had to be made there. Furthermore, the top battery slot was right where the Wii remote board would have to go if it's sensor was going to be in the right place.
To modify the battery compartment to work with two batteries, (and free up the top battery slot for the Wii remote board to lay in) I first had to yank out a couple of the metal terminals with a pair of needle-nosed pliers. The original negative terminal was tossed out altogether, but I was able to take the terminal that connected the (now unused) top slot and the middle slot, and turn it into the new negative terminal by breaking it in half. To get it ready to use, I just had to drill a hole in the battery compartment and run a wire to the new negative terminal.
The case had to be modified a bit to accommodate the Wii remote board. This involved cutting a few small notches in structural pieces, and a long slot in the battery compartment. This took a lot of trial and error to get right, and you can see it's not quite perfect, the Wii remote's board is sitting at a slight roll. I used a cordless Dremmel tool for this, but I probably could have used a razor blade if I'd had too, the plastic was pretty soft.
Three more modifications to the case were needed: A notch for the nunchuck cable, a hole for the "draw weapon" button, and a hole for the RE4/LCT switch. The nunchuck notch went at the bottom of the handle. The button went at the back of the gun under my thumb. I debated for a long time where to put the switch, but I finally settled on a spot just forward of the trigger guard. Mostly because it was easy to put it there, but also because it was out of the way. Again, I used a Dremmel to cut out these holes, being as careful as I could to match the two halves of the shell.
When I was sure everything was the way I liked it, I fixed everything in place with some dabs of hot glue. I like hot glue for projects like this because it's pretty forgiving of mistakes. You can pour in lots of it to hold components in enclosures not really designed for them, and you can cut it away if you have to. At this point the rumbler was still just dangling off the board, so I hot glued it right on to the board.
I'd been holding off on wiring in the power because it connects the two halves of the shell in an awkward way, but it was nearly ready to go at that point, so I soldered the wires from the battery compartment right onto what used to be the battery terminals on the Wii remote board. I had also forgotten to hook up the new speaker, so I did that too.
The case, almost but not quite, closed up perfectly. A little more work with the Dremmel and it went right together. It was a bit of a pain getting the slightly spring-loaded trigger to stay in place, I made sure to tighten the screws closest to the trigger first. The Wii remote board fits through the slot into the battery compartment as planned, and all the extra wiring and stuff fits without any serious problem. Unfortunately, the blue plastic thingy that had covered the blinky lights in the original gun no longer fit over the slightly bulky remote board, so that part of the gun is just open to the air.
Results :
The Good :
- IT WORKS! Yay. The gun works great in both Resident Evil 4 and Link's Crossbow Training, something no other retail gun can claim.
- The gun's speaker sounds better than the Wii remote's tiny speaker.
- RE4 is at least 100% more fun with a toy gun in your hand.
- Link's Crossbow Training is more relaxing with the nunchuck in the other hand.
The Bad :
- Lack of D-Pad. This was planned, but still sad. Maybe for Version 2.
- The home and power buttons don't work. These were both small flat buttons that I tried to solder onto the corner of. This was a mistake. I should have found a way to remove the buttons and solder right onto the pad.
- RE4's 'button mashing' moments are suddenly more confusing. I'll get used to it, though.
So, what did we learn? If you aren't afraid to potentially destroy a Wii Remote, and have some experience sorting out how electronic devices function, it is not impossible to make your own Wii Zapper. And if you're lucky you'll end up with something that'll work great regardless of which button is "Shoot", giving you more compatibility than currently available products.