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Designing For the Spirit of PLay

HOLLA is an interactive screaming battle. yell as loud as you can to shoot a beam of light from your mouth and defeat your opponent! Let off all your stress by screaming into the void!
My Role
My Team
Eric Kim — All
Project Duration
2 days (Hackathon)
Project Links
→ View the project on Devpost
→ View the project on
In February 2020, HackGT hosted their annual Art+Tech hackathon, Horizons. My teammate and I spent 2 days planning and building Holla with the intent of giving people a fun and memorable interactive game experience. For us, this was an opportunity to use our skills in the pursuit of play rather than efficiency or productivity related goals.
Why Horizons?

Going 3 years into my undergrad design studies, I had never participated in a hackathon before. I felt my major made me unsuited to hackathons as I didn't have a traditional Computer Science background as a design student at a tech school. But I knew that I wanted to do one before I graduated (my FOMO was acting up 😔). So I asked a friend who had never done a hackathon before either and we both signed up for the Horizons hackathon.

Our reasoning for choosing this hackathon was simple. The hackathon’s motto was “Where art meets tech”. As an artist and designer, the theme felt familiar to me in an otherwise unfamiliar environment. We wanted to have a fun hackathon experience to remember and we saw the potential of being able to make something that stretched our creative muscles.


Two Days to Execute

We had 2 days to conceptualize and build out our creation. We did not do any prior planning for the hackathon, instead we decided to do everything within the allotted 2 days given and have fun with it (self-induced pressure yay!). Our high level schedule consisted of us doing all our ideation and planning on the first day, then the next day we set to work buliding and programming.

Day 1: Ideation and Planning
Day 2: Build and Present


Initially, we whiteboarded some inspiration through open discussion. My teammate and I knew we wanted our thing to have some level of interactive gameplay. We also wanted our thing to have some absurdist and ridiculous element to it with a somewhat whimsical energy. Both of us grew up as huge Harry Potter fans and we thought the colorful visuals and magical element of it would work well for Horizons. We drew a lot of inspiration from the final battle between Harry and Voldemort.

The idea for a screaming battle came simply as we were chatting about how stressful college was. And we realized, hey! Wouldn't it be nice to be able to scream into the void whenever we wanted to release some stress? But make it even better! Have people scream at each other!


Once we had our idea, we began sketching what we envisioned our contraption looking like. Like how Voldemort and Harry's wands clashed in a colorful duality, we wanted a similar effect with our contraption. We envisioned a light tunnel that waxed and waned depending on the player's voice.

pictured below: one of the sketches we did of what we wanted Holla to look like. here we were laying out measurements for our build.


We began construction the very next day after we had our sketch and idea laid out.
Supplies we used:
Adafruit DotStar Digital LED Strip
ELEGOO Big Sound Sensor x2
12"x24" 1/8" Clear Acrylic Sheet x3
12"x24" 1/4" MDF Board x1
8ft 2"x4" Wood Stud x1
Electrical wires

Here are all the tools we used:
Lasercutter(Laser engraver)
Woodworking Tools (Bandsaw, Miter saw)
Electronics Equipment (Soldering iron, Wiring kit - wires, wire strippers, electrical tape, solder, etc.)
Basic Tools (Hot glue gun and hot glue sticks, superglue)

We constructed chambers out of lasercut acrylic that the players would scream into, this is also where our microphones were located.

Creating Repeatable Patterns

For the construction of the tunnel itself, I drafted a file with the circular components we would be using. These were very simple cutouts, a single circular piece of acrylic with 2 custom pieces of MDF (Medium-density fibreboard) that has a slot cut out in the buttom to house the LED strip we would use to simulate players' voices.

We didn't have a lot of time for construction so instead we spent a couple hours planning our design so that it could quickly be executed through repeatable components cut out by the lasercutter.

pictured below: one of my cutout files that I am positioning on the lasercutter!


Once the tunnel and chamber were assembled together, we finally had Holla's basic structure completed.


The programming behind Holla was relatively simple. We powered it with a single Arduino Uno. Once we connected the microphones and LED strip, we essentially just set up our program so that when a player screams into the microphone, the LED strip will light up, the higher the volume, the more lights will light up in succession. When two players meet in the middle, light will move towards the other side based on who's volume is louder.


Playing the Game

The game is played by 2 players. Both players scream as loud as they can into the sound chambers until one completely fills all the LEDs with their color. Screaming louder pushes a player's beam further towards the other side. When the two beams meet, they push against each other and the movement is determined by the difference in the screaming volumes.

Final Product

Let's Play

Once we finished constructing, we had various other hackathon teams and HackGT staff test out our game. I now have a treasure trove of amazing video clips of people screaming their heads off at each other. 😂 We let people play around with our game, and I think everyone had a really fun time!

View a demo of how it works below!


I had such a blast making this. It also really let me use a lot of the skills I had developed in interactive product design and fabrication. The most memorable part of the entire experience I would say though, was definitely seeing other people use our game. It was full of a lot of laughs and I was happy that we were able to make this goofy little game a fun experience for people.

Now enjoy some photos from my time at the hackathon!

Horizons 2020