I had a grand, academic ambition when I started my final project. My midterm, Pitchy Bird, had successfully used vocal pitch to control a character. For the final, I wanted to escalate the complexity to gamify the Implicit Association Test (IAT). The concept was Flappy IAT, a game where players navigated by physically “bumping” a controller while simultaneously tilting it left or right to categorize words (e.g., “Good” vs. “Bad”) displayed on pipes.
It sounded brilliant on paper, a lesson to learn in practice… A lesson on how an ambitious outlook (conceptual AND technical) can suffocate user experience.
User Testing
My game’s initial prompt for the user was: “Bump to fly, Tilt Left for Green/Good, Tilt Right for Red/Bad.”
There was immediate confusion when I described it to people and even later handed a prototype to them without instructions. The cognitive load was too high to keep the bird afloat WHILE processing semantic text on moving pipes. This has become clear immediately after user testing, even with a keyboard-simulated prototype.
Even when the users understand the game control logic, “Bump” didn’t play well physically. Users weren’t sure if they should tap the device or shake it. The motion was actually a “Wave” and a sudden vertical movement regardless of the angle. I decided to changethe internal and external naming from BUMP to WAVE, which made the game sound nicer and action more intuitive.
Technical Challenges
Behind the scenes, the technical implementation was really a “battlefield”. I was using an Arduino with an MMA8452Q accelerometer sending data to p5.js via Web Serial.
Calibration Nightmare
In the first iteration, I assumed the controller would calibrate itself and has some error tolerance. None. Hardcoded thresholds (e.g., expecting 1.0g on the Z-axis at rest) failed the moment a user held the device at a comfortable, natural angle.
I had to write a manual calibration routine calibrateRestPosition() that runs at startup. It takes 20 samples to establish a “zero” baseline for the user’s specific grip, allowing the game to detect relative changes rather than absolute ones.
Sensitivity Tuning
Initially, the bird was sluggish. Users were waving frantically with no response, or triggering two responses as they waved up AND down. The threshold was set to 1.0f (requiring 1g of force above gravity) and bidirectional. I had to lower this to 0.5f to make the “Wave” detection feel snappy and responsive, and one-directional so you go down to “Bump” the bird up.
Killing the IAT
Note that I had built elaborate logic for stimuli arrays, category pairs (like “Female Doctor”), and complex CSV logging for reaction times. But I looked at the codebase and the user experience. The game wasn’t fun. It was stressful and buggy.
The IAT logic was causing errors in the drawing loop, and the “Game Over” screen was breaking because the state management between the IAT trials and the physics engine was out of sync. Users were dying because they lacked familiarity and the buggy interface.
I commented out the entire IAT part.
- I removed the word overlays and the tilt logic.
- I optimized the Arduino code to stop listening for X/Y tilt axes entirely to save processing power.
- I refactored the name from Flappy IAT to Wavy Bird.
Refining Core Experience
Once I removed the “noise” of the psychological test, I could focus on making the actual game better.
- The Tutorial: I noticed users could die instantly upon starting. I introduced a “Tutorial Mode” where collisions don’t kill you but reset the bird position.
- The “Game Over” Loop: A persistent bug caused the screen to go blank upon death instead of showing the score. I fixed the state transition so that
handleCollisioncorrectly triggers the Game Over screen, allowing for a restart without refreshing the page,.
Conclusion
The project I ended up with is smaller than the one I proposed, but I would say it’s a trade-off, particularly when I am managing three final projects for this semester. By cutting the IAT feature, I could focus more, making the game from a broken research tool to a polished physical game.
If one has to explain the controls for five minutes before someone can play, the design is too complex. Sometimes, we just need to wave.
