A 12-foot-tall Electric Guitar

Ever imagined yourself playing a 12-foot-tall Electric Guitar? Well, if you’re based in Kansas City, you could have the chance to rock the Boulevardia festival. But, what is this super tall guitar we’re talking about? It’s a project that Chris Riebschlager from Dimensional Innovations made for the festival.

We were so impressed by this guitar and curious to find out more about its construction, so we caught up with him and asked him everything about his gigantic instrument.

Hi, Chris! We recently came across this very cool 12-foot-tall electric guitar you built. Can you tell us a bit more about the project idea?

My team was invited to create something amazing for Boulevardia, a two-day festival that’s all about music, food and beer. Our job was to create something big, iconic and interactive for the welcome center. Over 40,000 people attend the festival, so I wanted to make a big impact.

A co-worker had introduced me to the Bare Conductive Touch Board and I had been trying to think of a way to incorporate it into a project. When we decided we wanted to create a huge, playable guitar, the Touch Board was the obvious choice to make this project work. After some initial prototyping with the board to make sure it would work, we were off to the races!

We assume it was a challenging task. Can you tell us more about your background?

Most of my career was centered around web development, but I had always felt the itch to do something more tangible with technology. That desire eventually led me to an opportunity to create several interactive installations for the Nelson-Atkins Museum of Art here in Kansas City. After watching people interact with my work there, I was hooked.

Over two years ago, I landed at Dimensional Innovations, where I now lead the software development team. I get to work with sculptors, engineers, fabricators and designers in a 60,000 square foot factory space where we make all kinds of amazing things.

We’re really pleased that you used the Touch Board to prototype the electronics part. Can you give us more details about the technical part?

The Bare Conductive Touch Board was such a natural fit for this project and I couldn’t be happier with how well it worked. Each guitar string is made of 16 gauge galvanized wire and is routed down to a cavity inside the guitar where the Touch Board is mounted. The galvanized wire is joined to a much thinner wire connected to the board with alligator clips.

The Touch Board is running a very simple script that sends serial messages when touch events are fired. For this project, I needed to know when a player had touched a string and when they had released it.

I used a Raspberry Pi for the interface and sound generation portion of the guitar. I have 16 buttons that are wired to the GPIO pins on the PI. These allow a player to pick which chord will play when they strum the strings. It also allows them to switch the guitar into “clean” or “dirty” mode.

The Raspberry Pi is running a Python script that responds to the serial messages sent by the Touch Board and responds to button presses on the front panel of the guitar.

When a string is released, the Pi plays the corresponding note for that string and the selected chord. When a string is touched, it quickly fades out whatever sound that string was previously making, much the same way an actual guitar would behave.

I then routed the audio out through the HDMI port on the Pi to an HDMI/VGA adapter and then plugged the whole rig into a Kustom stage monitor. It was plenty loud!

Between the Touch Board and the Pi, there was very little latency so the guitar felt extremely responsive. It stormed both nights of the festival and it was nearly 95 degrees and crazy humid each day. But both the Touch Board and Pi worked perfectly. It’s still working great and the guitar is going to be installed in our shop now so we can show it off.

How did you record the notes? Did you use any particular programme?

To make this work, I needed a library of isolated guitar notes, both clean and distorted. I tried to record the notes with one of my guitars, but I wasn’t really happy with how it sounded. No matter how hard I tried, I couldn’t get nice, clean notes that were all the same duration and volume. It sounded like a mess when I played six of them together.

What I ended up doing was creating the sounds in GarageBand. I just had a single guitar track with a single note. I’d set the note to E, export the song. Change the note to F, export the song and so on. At the end of that process, I had a pool of completely realistic guitar notes that were all the exact same duration and volume. Plus, there was no amp, hum or extra string noise.

Did you encounter any difficulties of using the Touch Board and if yes how did you overcome them?

The Touch Board was actually the one part of this project I had absolutely no trouble with. I was initially concerned with how it would behave after connecting it to 60 feet of galvanized wire. I wasn’t sure if the capacitive touch would behave as expected through that much metal, but it performed like a champ.

Once we brought the guitar back to the shop, we wound two strands of wire together for each string to help keep the strings straight and tight. So the board is now attached to 120 feet of galvanized wire and it still performs perfectly without having to tweak the sensitivity settings.

A 12-foot-tall guitar is not something simple to build. Can you tell us more about the fabrication and engineering process?

DI has an amazing team of engineers and fabricators. They had the extremely tricky challenge of making a guitar this size that is completely free-standing with no visible supports.

The guitar is made of sandwiched layers of MDF which were cut on one of our CNC machines. Each layer was precisely cut to allow spaces for the internal electronics and to remove some weight from the overall structure. There is a tube steel frame that extends from the bottom of the guitar and then up the length of the neck to provide a strong internal structure.

Once it was assembled, the team rounded and bevelled the MDF to match the contours of an actual guitar. It was then primed, painted and clear-coated by our paint department. We also designed and printed nearly 100 vinyl stickers representing all the bands and breweries who participated in Boulevardia.

A steel construction base was made that housed RGB LED lights that cycled through colors throughout the night and up-lit the guitar really nicely. To install and deinstall it, we used a truck with a crane to drop the guitar into place on its base.

From concept to completion, the whole process took less than five weeks. I think that is a great example of how insanely talented and hard working our team is.

What was the best moment of watching the audience interacting with the guitar?

With many of our installations, we include some type of instructions for visitors. I purposefully excluded any printed instructions for our guitar. I wanted people to discover the functionality on their own without prompting.

The best moments were seeing the surprise on people’s faces when they found out they could actually play the guitar. That’s exactly what I wanted to evoke with this installation. I wanted to encourage people to explore and experiment and be surprised. In a lot of ways, everyone at the festival told ME how they wanted to play the guitar, not the other way around. It felt so great every time I heard a “Wow!”, “No way!” or “That’s awesome!”

You’re in a very creative environment. Any upcoming plans of using our technology in the future?

Absolutely. Part of my goal with this project was to demonstrate that incorporating technology and interactivity into a project doesn’t always mean that there’s a touch screen or a projector. To me, the best interactive installations are the ones that don’t look like interactive installations.

The guitar project got several brains at my company churning on potential ideas for future projects. We’d like to experiment with using conductive paint to add interactivity to more of our sculpted and fabricated pieces.

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