I built an arcade machine to play various games and wanted a light gun of some sort to play shooting games. After looking for some time at a few different options that cost $100usd or more I decided to make my own. I saw that there were a lot of people using Wii remotes and a Mayflash Dolphin Bar to emulate light guns and though it would be the best and cheapest choice for me since the Dolphin Bar was $20usd and I had a bunch of Wii remotes laying around. I did some digging around for designs to 3D print and looked around for cheap toy guns and didn't really see anything I liked or that would look good. I had seen that someone cut the top off of an NES light gun and basically glued a Wii controller to the top, it seemed like the perfect gun for my setup. I thought that it seemed silly to have a controller stuck to the top though so I decided to see if I could cram everything inside of the gun.
Step 1: Parts and Tools You Will Need
NES Zapper -
Wii Remote (I used a Plus because I had one laying around.)
Dolphin Bar -
18 AWG Wire
Hot Glue Gun
47 OHM Resistor
22 OHM Resistor
6 Ft USB Cable for Power
Step 2: Make Sure Everything Works
Start off by connecting the Mayflash Dolphin bar to your computer through USB and sync your Wii Remote to make sure everything works as it is supposed to. The Dolphin Bar stores the Bluetooth sync information so you won't have to re-sync later on even if you change computers.
Step 3: Taking the Controller Apart
Start by removing the 4 tri-wing screws behind the battery door. After removing the screws pry the case apart towards the trigger button. It's held together by two snap together tabs.
Step 4: Desolder Components
There are 10 solder points for the IR sensor at the front of the controller board that you will need to keep in tact to re use later on. I chose to remove the accessory connector but you can leave it on since that portion of the board will be removed anyway. I also removed the vibration motor, sync button, battery spring pads, and the capacitor. I chose not to use the motor in the final design but you will need the capacitor and you can use the sync button later on. The capacitor needs to be re-attached to the negative pin and the TP1 pad on the controller.
Step 5: Power Supply
The Wii remote works off of two double "A" batteries which provide approximately 3VDC. Since I'm running this setup in an arcade cabinet I'm pulling 5V power from a computer power supply and stepping it down to 3v and I decided to use a breadboard to hold the components. You don't have to do this but it made my setup easier. You can use a USB cable and cut the unused end off. Trim back the wires and cut the white and green ones off because you won't need those. Trim the black and red wires and tin the ends with solder. Solder the 47ohm and 22ohm resistor in series and attach them to the red wire. Since I am using the circuit board for the power supply and the 4 strand wire that came with the Zapper, I decided to use two of the wires for the sync button placing the button on the circuit board and soldering the other ends of the wire to the pads on the controller board in the gun for the sync button. The Dolphin Bar stores the sync information, but you never know and I'd rather not take the gun apart if I need to re-sync the controller for some reason in the future.
Step 6: Re-attach IR Sensor
You will need to cut 10 pieces of wire for each of the pins on the IR Sensor. The pads are delicate so after I was done soldering all 10 of the wires to the sensor I used hot glue to keep everything in place. I did the same with the pads on the controller board. I used 12 inches of wire to extend the IR Sensor before I had a final layout of the case. Realistically I could've used 3 to 4 inches. I didn't want to risk breaking anything so I left the wires at the length I used and just coiled it in the case after. Before continuing make sure that the sensor still works by attaching your power supply to the positive and negative pads on the controller board.
Step 7: Inside the Zapper
Looking inside of this aftermarket zapper, things look really simple. In my design I used the cord that comes with the gun and just made new ends for it. if you are using a USB cable or have other plans you can get rid of everything inside of the case except for the trigger and trigger button. I chose to leave the trigger and trigger button there because it's simple, it's already in the perfect spot, and it works. I also cut off one of the screw posts on the right half of the case. You can leave the corresponding post on the left half of the case.
Step 8: Trimming Down the Circuit Board
I used the Wii remote circuit board scans I found here to trace out a cutting path for the Wii remote. I found that using a dremel was the easiest way to cut down the board. Make sure you use the scans and verify that you aren't using a different controller or cutting traces you shouldn't. The controllers have double layer traces on both sides so you have to make sure through all four layers that you aren't cutting something you shouldn't. Using the trace pattern shown above you remove some dead space in the circuit board, the connections for the rumble motor, the LED status lights, and the connector for the accessories. It will also cut the on button in half so you'll need to de-solder that as well from the two pads on the right side of the button. Solder a tactile button to those two pads with a few inches of wire and the on button still functions. I decided to put my on button at the bottom of the gun by where the cable goes in to avoid it being pushed accidentally. Again, after you cut the board attach power and make sure the remote still works.
Step 9: Button Placement
I chose to have my power button at the bottom of the gun next to the power cable to avoid accidental pushes. I also chose to only put two buttons on the right side of the gun. You can add more, but they each need to have a corresponding button on the controller board to solder the wires too. Remember that the trigger will be connected to the "B" button on the controller board. I simply drilled holes slightly larger than the button heads and hot glued them into place.
Step 10: Connect the Buttons
Looking at the button pads you can see that they are broken into a left and right side. Simply solder two wires to each button pad set, one to the left pad and one to the right pad. Solder the other ends of the two wires to the corresponding button on the gun case. The circuit board should fit nicely between the post for the trigger switch and the case. When you replace the trigger it should not rub against the controller board at all. I used a few spots of hot glue to secure everything in place. I tried to get the IR Sensor as centered and square as possible. It doesn't have to be perfect. Make sure that the wires for the sensor are on top otherwise it will be reading upside down.
Step 11: Wrapping It Up
Connect the power wires to the positive and negative terminals on the board and close everything up. Make sure none of the wires get pinched and you should be ready to go.