How-To: Build a 'Guitar Hero' foot pedal controller

Benjamin J. Heckendorn returns from a vision quest of Xbox 360 laptop-building and Jasper-hunting to share a new how-to project with Engadget readers. In this episode, he'll describe how to build one of his Guitar Hero foot pedal controllers, which allows those with physical limitations to play their favorite guitar rhythm games using a foot pedal! Read on for the complete how-to.

Building a Guitar Hero foot pedal controller

First I should clarify that this will work with either a Guitar Hero or Rock Band controller. It would seem in the world of fake plastic guitars they're all pretty similar.

As seen in the highly technical drawing above, we're going to replicate 3 functions of the guitar onto the foot pedal in this project, specifically:

• Up strum - Click up with your foot.
  

• Down strum - Click down with your foot.
  

• Whammy bar - Lift heel.
  

The first time I built one of these I tried a separate pedal for the whammy bar, but it was actually harder to use... I guess the brain just isn't wired that way.


Stuff You Will Need:

• A game guitar. Unlike the great Game Guitar Shortage of Ought Seven these are pretty easy to find. You can use pretty much any kind you wish that is compatible with your game system. Last time I was at Best Buy they were still trying to unload all their GHIII stuff, guitars were piled everywhere, and the markdowns were considerable. I think at some point in the future there will be so many plastic guitar games that Best Buys will actually be constructed OUT OF the piles of them.

• (2) hefty pushbutton switches. If you're using a Guitar Hero axe you can probably use the switches found inside, however Rock Band axes use several different methods for the strummer and thus you'll probably need new switches. I'd suggest snap action switched / limit lever switches (they go by many names) as then are easy to mount and have a very postive "click" when activated. I personally mod all of my fake guitars with these right out of the box. But really, any kind of momentary pushbutton switch will work, hell, even a doorbell ringer.
  

When wiring these types of switches, use the NO and CO connections, as shown above.

• An old controller cable of some sort: This will connect between the guitar and pedal. You'll need to find one with at least 6 wires inside as that's what we'll need. Good candidates include: old PS1/PS2 controllers, old Genesis controllers, VGA cables. Really any sort of wire bundle/ribbon cable, anything with 6+ wires will work.

• A couple of springs: A smaller one for the strum clicker, and a beefier one for the whammy pedal. Before you go and pull apart a bunch of pens I'd suggest instead just buying some springs from the local hardware store. They cost more but will work better. See how-to for more details.

• A bit of PVC pipe and a dowel: This is used to make the axis of the pedal. There's plenty of ways to make the pedal rotate, this is mine. I'm using a 1/2" inner diameter PVC pipe and 1/2" outer diameter wooden dowel.
  

• A curved piece of something for the clicker pedal: Not very specific, I know. But again, use whatever feels best. I'm just going to be using a piece of 4x10" metal from the little "Build with Metal" kiosk at the hardware store.

• Some wood/plastic/etc to build the pedal out of: Be creative, use whatever is handy and/or cheap! I'll be using small wood planks and song tag board from Ace Hardware in this example.
  

Tools You Will Need:

• Hot glue gun of course. And glue sticks. Can't forget those.
  

• Soldering iron, solder, extra bits of wire.

• Electric drill.

• Several drill bits, large enough to cut holes and countersinks for the dowels and springs.

• Various screws, fasteners and wood glue.
  

Step 1: Modding the Guitar

All right let's get this party started. The first step will be to mod the guitar - in this example we'll be using a Guitar Hero III Les Paul for Xbox 360. Please have your glue gun and soldering iron fired up and handy!

Start by ripping apart the guitar. Depending on manufacturer you may need a star driver bit, Phillips or whatever you happen to find. Be sure to disregard all warranty-voiding stickers, that's just the man trying to bring you down.

Here's the strum area of a Guitar Hero III controller. As we can see there's 3 connections, ground / common, up and down. These will be 3 of the connections we'll need in the cable.

Next let's look at the whammy bar. It uses a full-sized potentiometer, typically mounted as seen above. At this point we'll use some colored markers to mark the potentiometer and how it relates to the wires. (In the example above one of the wires was already red) This way we can keep track of it later for proper wiring. Here I have labeled them "red", "wiper" (the center pole is always the wiper, the thing that "wipes" across the potentiometer) and "other". These connections comprise the other 3 wires we'll need in the cable.

By the way I'm going to call the potentiometer "pot" from now on since that's the proper slang and it'll save Engadget several bytes in bandwidth.

Let's talk about the whammy bar a little bit more before we move, since this is the trickiest part of the project. The top photo shows the bar in its default, non-whammyed position. Bottom photo shows the position of it when whammed. It's *roughly* 30 degrees of rotation.

Keeping track of the flat edge of the pot is very important. The pot must be reinstalled in the same orientation as factory for it to work.

What we are going to do is put the pot on the OTHER side of the whammy bar (or pedal in our case) and thus flip its functionality, as shown above. When the pedal is depressed by the ball of your foot it will be in No Wham mode, and when you release your foot the spring pushes it up, into Whammed mode. Make sense? Note how the flat edge of the pot is level with the whammy bar / pedal at all times (photo above shows it in no wham position) This is very important for us to keep track us.

NOTE: Depending on your guitar the "no wham" position of the pot may be different. Please check the angle of the flat edge of the pot when you pull it from the guitar to be sure.

Ok let's wire up our controller cable to the guitar. As mentioned we need 6 wires total, though it's possible some guitars may have 4 separate wires for the strummer thus requiring a total of 7. I drilled a hole in the side of guitar for the cable in this example.

Almost any sort of cable worth its salt will have colored wires. Wire each one up to the connections in the guitar and note which color goes with each function. In this case:

BLACK-STRUM GROUND
BLUE - STRUM DOWN
BROWN - STRUM UP
RED-POT RED
YELLOW-POT WIPER
PURPLE-POT OTHER

I have a couple notebooks filled with all the custom pinouts I've done over the years, it's a very good thing to keep track of during a project. Once you've got it logged down go ahead and put the guitar back together, it's done!

OK let's make the pedal itself. Start by bending a 4x10" piece of metal (or thereabouts) into a shape like shown above. I bent mine around a PVC pipe. This is what the foot will contact. Drill 2 small holes in the crotch of this thing (yes I just said that) for attaching the axis.

Next drill 2 matching holes in a piece of 1/2" PVC pipe to match, and secure it to the metal pedal with screws. Be sure the holes are in a ways so the wooden dowl can plug into the ends a far distance.

Good thing I was wearing intact socks.

Now let's rough out the base. I'm using some 1/2" x 5.5" pieces of wood from Ace because they fit in my car. Mark off the point near the small of the foot - this is where the whammy pedal will begin. Cut off the main piece of wood at this point.

Next let's frame up the side pieces. Putting the base piece on some graph paper - with a ruler to boot - is incredibly scientific and should make this an obvious piece of cake. Using this, mark off the size of your side pieces (I'm making the 4" tall) and also decide where the pedal axis (the PVC pipe) will be in relation to them.

Two main things to check here: First, be sure there's about a 1/4" gap at the front of the pedal, because it needs some room to depress down. Secondly, we'll need some room above the pedal (near the axis) for the up switch. How much will depend on the kind of switch you use, so make sure you cut the side pieces tall enough to accomodate this.

With the side pieces cut, decide where you'd like the axis to be and countersink holes in either side to fit the wooden dowel inside of.

Both side pieces with matching mirrored holes.

Countersink a small hole under the pedal in the center and place a spring inside. The idea it will push the pedal back up with enough force to release the switch. Otherwise after you click the pedal down it may remain stuck "on". Please note the top swith will not likely require a spring because it's got the wonders of gravity working for it.

Cut small lengths of wooden dowl and insert them in the axis holes and the ends of the PVC. If you use 1/2" ID (inner diameter) PVC with 1/2" dowl it'll be quite snug, and will rotate within the side pieces, rather than on the pipe itseld.

Again, this is simply how I did it, there's zillions of ways to make the pedal rotate in your own project, use a door hinge even!

I always keep insulating foam tape around, It's very useful. In this case we can use it to pad sections of the pedal, such as where it contacts the spring or switches.

Foam strip on pedal lined up to cushion against spring.

OK let's put the switches in! Again this will depend on what kind of switches you use, here I am using snap action lever switches since I like them and they're tough. The kind with roller levers work great, though they cost a bit more.

Position the switch in what feels to be a good place and try clicking the pedal down onto it. The edge of the pedal should push against the spring first, switch second, and then hit the wooden base. When released, the spring should push the pedal up far enough to release the switch. To find the best spot, slide the switch forward and back under the pedal until it works and feels right. When you find the spot, hot glue the heck out of it.

Do the same for the upper switch. As seen above, a top portion has been installed, mostly to accommodate the upper switch. As mentioned before, gravity will be pulling the pedal down, so you don't have to worry about the upper switch getting stuck "on". Most of the time I find gravity annoying, but it's useful here.

Pretty simple so far, let's complicate it a bit and install the whammy pedal. I had an extra metal one laying around, for your project of course feel free to use whatever (Busted Rock Band pedal perhaps).

Note the position of the pot - it is on the opposite side of how we found it in the guitar. Also note the 3 connections to it. In the above photo it is in the no wham position, as if a foot was resting on it. The flat edge of the pot should be DOWN, or parallel with the pedal.

At this point attach the pot to the pedal. For mine I used a thin hollow metal tube from the "Create with Metal!" section at Ace. The tube I slid over the pot, then drilled the pedal to it. One of the screws goes through the shaft of the pot, thus making it rotate with the pedal.

Again, be sure that the flat edge of the pot is facing DOWN, as shown above, and is parallel with the pedal when you screw them together. It's easier to do it right first than fix it later. As you can see, I've covered some of the pedal with black felt padding so it looks a little nicer.

Using some 1/4" material (tag board was used here) make a full-sized base for the pedal assembly. It should reach from the front switch section all the way to the back of the whammy pedal.

Next let's mount the potentiometer. Using small pieces of tag board, mount it as shown to the edge of the board. The surface of the whammy pedal should be flush (level) with the main base of the unit.

Cut a matching mount for the other side and slide the pedal into the holes. (Tag board comes with free holes). Be sure to attach the side mounts well since they'll be under duress in use. I'm using wood glue, clamping it, hot gluing the insides, then drilling screws in from the bottom as well.

Next install your larger spring between the pedal and the main base, as shown above. To make up for the spacing gap I've also cut a pedal-shaped extra piece of tag board as a backstop. This also gives me something to countersink a hole for the spring into.

End view of the spring. For easy mounting, simply hot glue it into the countersunk hole, but I'd suggest testing the unit first in case you can to adjust the angle.

Next we'll wire the pedal to the controller cable. Using some spare wire or ribbon cable, wire the pot to the back of the pedal. In my past pedals these wires were hidden, but this project isn't intended for any beauty pageants. Note that in this picture the pot is positioned in a manner similar to the original guitar.

Finally, wire the pot wires and pedal switches to the controller cable using the color coding guide you surely wrote down back when we modded the guitar.

And that's it - the guitar foot pedal controller is ready to rock, literally. Remember the trickiest part is the whammy pedal, but if you build it as shown it should work right off the bat without any adjustments necessary.

Hopefully this How-To will help people build this mod for people they know in need, and encourage fake plastic guitar modding in general. Have fun and RAWK ON!

The above finished project will be donated to first eligible reader who requests it. Please send an email to Ben at: Benjamin.heckendorn [at] gmail [dot] com

Read - Adobe Illustrator file detailing the project