Slide Pad: a Customized Video Game Controller
Introduction: The Street Fighter series is one of my
favorite videogame franchises, and I had a great time when Street Fighter IV
was released for the Xbox 360. I have spent over one-hundred hours playing that
game, and I don’t want a single one of those hours back. Street Fighter IV came out
when I was in graduate school, and it helped take my mind off the lab.
After a stressful day at work, I could count on some fun and excitement waiting
for me at home.
To gain even more enjoyment from the game, I purchased a Tournament Edition arcade fight stick from Mad Catz. The fight stick was a built with authentic
arcade hardware: joystick and buttons made by the Sanwa Denshi Corporation of
Japan. These were the same parts used by Daigo Umehara, the famed Street Fighter champion who was know for practicing exclusively in Japanese arcades. I loved using my fight stick to master special moves and combos, but
after so many repeated button presses, I ran into a problem. My beloved fight
stick was causing a recurrence of carpel tunnel syndrome in my wrists.
I had battled and evaded carpel tunnel in the past by
swapping my conventional keyboard out for a Microsoft Natural Ergonomic Keyboard (a product line that I highly recommend). However, this time,
switching wasn’t going to be as easy as logging in to my Amazon account and making a purchase; there
weren’t any ergonomic fight sticks on the market. For the sake of my wrists, I
decided to stop playing as much and eventually moved onto other games.
Still, the idea of an ergonomic fight stick never left me, and I kept
thinking about how I might build an ergonomic fight stick or otherwise
circumvent the problem of carpel tunnel induced by traditional fight stick use.
I decided that an alternative path would be to use a fight pad: a handheld
controller specifically designed for fighting games. I purchased one from
Amazon, but I found that its directional pad was nowhere near as precise as a
Sanwa joystick. Unimpressed, I bought a second model that seemed to have a more
promising design, but it too fell short, malfunctioning after a couple weeks of
use. Fed up, I decided to come up with my own design.
Project Goal: I decided to build a fight pad that would
mimic the functionality of a Sanwa joystick. The Sanwa joystick in my arcade fight
stick was perfect for Street Fighter IV because the stick had a square gate.
This means that the joystick’s motion is restricted by a square-shaped piece of
plastic, which for most who play Street Fighter on a
regular basis, is the preferred gate shape for executing the moves required
by the game. No handheld controller that I could find was a proper fit for the
task; most had circular gates surrounding their directional input devices
(thumb sticks or directional pads), and the one square-gated controller I did
find had was awkward to use and had a sub-optimal button layout. So, my only
choice became to design and build my own fight pad with a square gate and a
suitable button layout.
Choosing a Platform for My Prototype: I began by looking
into an accessible electronics platform. I knew that it would be technically
complex to design a controller for the Xbox 360 (a platform that defaults to 13
button inputs and 3 directional pad inputs), so I decided to start with
something simpler: the Nintendo NES (four button inputs and one
directional pad input). Making an NES controller with fight pad functionality
would be fun, because I would get to produce my controller for a great system
(I love the NES!) and work on a smaller budget (NES controllers go for about
$7 apiece (three times cheaper than a used Xbox 360 controller), and fewer buttons per controller means less money spent on both
buttons and wires). Further, the minimalistic nature of the NES controller
meant a quicker development cycle, because takes less time to build and wire a
controller with fewer buttons and directional inputs.
My First Prototype: I knew that I would
ultimately need to construct a handheld controller, but those are tough to build because they require the builder to work within a confined space. Larger
controllers (fight sticks) are easier to build, because they allow the builder
more room to experiment, fail, and regroup. So, even though I ultimately wanted
to build a handheld controller to avoid suffering from carpel tunnel induced by
a traditional-style fight stick, I built a traditional-style fight stick for
the NES to gain experience as was a more accessible first step.
To build this prototype, I salvaged a cardboard box from my
recyclables and used a box cutter to cut holes for a Sanwa JLF joystick (the same
used in my Mad Catz Tournament Edition fight stick for the Xbox 360) and Happ
arcade buttons (I had these on hand; they’re not as nice as the Sanwa buttons
in the Mad Catz stick, but they’re still an upgrade over the buttons in any
first-party NES controller). Next, I removed the PCB (printed circuit board)
and signal cable from a used NES controller and soldered wiring for the buttons
and joystick. I then made the appropriate connections and crossed my fingers.
Result: The stick worked! I was super happy to see that I
had created a functional NES fight stick, and I tested it for days. It instantly became my favorite piece of electronics! Still, the fight stick was not perfect and
helped me understand how to improve my process in order to create the more
technically daunting handheld fight pad.
Self-Critique: The wiring was functional but not
neatly done. To avoid having this problem with my handheld controller, I
purchased quick-connect wiring online from the Paradise Arcade Shop. Another purchase
from that store included a set of micros witches to replace the Sanwa JLF and a
set of four smaller buttons (Sanwa this time) that would be more appropriate
for a handheld device.
The Handheld Fight Pad–Box Construction: I started by
making paper prototypes for the cardboard case that I would eventually use to
house the controller. I used paper for initial prototyping because I wanted to
conserve cardboard and needed to quickly make several case prototypes. I
eventually arrived at a case that measured 6 in x 3.5 in x 1.5 in. I then
replicated the paper case with cardboard and made sure that it folded flush.
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| Unfolded Paper Case |
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| Unfolded Cardboard Case |
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| Folded Cardboard Case, Edges Flush |
The Handheld Fight Pad–Buttons and Switches: I arranged the
micro switches inside the box, and I bent them slightly to provide a good fit. Then,
I used hot glue to affix the micro switches to the box, and I used a box cutter
to remove a square-shaped piece of cardboard from the box so that a thumb
slider could be placed inside. I used a Dremel Rotary Tool to cut holes for the
buttons, and I was glad that the leads from the button for my index finger
did not overlap with those from the button for my thumb.
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| The top wire does not fit, because its lead is not bent. |
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| The micro switch leads are bent to accommodate wiring within the case. |
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| Circular holes fit the buttons, and a square hole allows access to the micro switches. |
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| The thumb and index-finger buttons both fit within a compact space. |
The
Handheld Fight Pad–Soldering and Wiring: Now for the hard part, I had to
solder wires for the buttons and switches to the PCB from an NES controller.
After soldering small wires to the PCB so that the button and switch wires
could be connected to it, I found that the PCB took up too much space within
the box. So, I discarded the PCB and soldered a separate one, this time laying
the connecting wires flat. The new design allowed me to fit all of the wiring
in the box, which I glued shut after testing that all of the connections
functioned properly. Unfortunately, I found that the wiring pressed too tightly
against the micro switches and prevented them from functioning, and I also found
that a wire had come loose. So, I unglued the box, added a piece of protective
cardboard to prevent the wires from touching the lever arms of the
micro switches, and used hot glue to hold the wiring in place on the PCB. I
closed the box, glued it shut, and hoped for the best. Everything worked!
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| The wires are soldered vertically onto the PCB. |
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| This doesn't look promising. |
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| Indeed, the board won't fit into the case. |
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| Horizontal soldering to the rescue! |
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| A protective plate covers the micro Switches, and the tied wires fit nicely into the case. |
The Handheld Fight Pad–Thumb Slider: I was finished
except for the big payoff: a thumb slider that would allow me to replicate the
precision and accuracy of an arcade joystick. I began by thinking that a small
stack of dimes would fit well inside of the thumb slider opening, but dimes
were slightly wider than was necessary and tended to push multiple directional
inputs at once, making my character face one direction and move in another when
I tested the prototype. So, I looked around my house for something of diameter slightly
smaller than that of a dime: the cap from a tube of Chapstick! I glued two Nintendo
buttons together, affixed a small buffer disk from my Dremel kit, and covered
the disk with the cut-down cap from the tube of Chapstick. The sliding
mechanism worked! However, it needed stabilization. I cut an appropriately
sized hole into a small piece of cardboard and slid it on top of the buttons; I
later added hot glue to further stabilize the cardboard piece. Finished!!!
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| Just a Bit Too Wide |
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| Just the Right Size! |
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| After Some Slight Modification |
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| Pieces in Place |
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| Fully Assembled |
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| Functional, but the Slider is Not Stable |
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| Much More Stable Sliding |
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| Finished Product!!! |
Reflection and Next Steps: I love that I was able to create
an arcade stick from parts, and I am thrilled to have a working slide pad
prototype. This project taught me a ton about working with electronic
components, and in the process I built two prototypes that are a lot of fun to
use. I am glad to have brought my vision to life, and I am excited about the
future for this project.
The slide pad provides innovation in directional input,
component selection, and overall construction for a handheld controller. In
addition to its novel directional input mechanism, the slide pad uses authentic
arcade buttons and switches, and it was custom-fit to my hand. Few controllers
use round buttons as triggers, but by customizing the slide pad to my hand, I
made the round button implementation work. The world doesn’t have a truly customizable controller option, at least not in the way that it has
custom-fitted clothes and sports equipment; perhaps my product could create a
market for custom-fit controllers? I can’t wait to extend this project by using plastic (likely 3D-printed) casing and, ultimately, an Xbox 360-compatible PCB.
