The SNAIL : an Esp32-powered Sensory Neurofeedback Acoustic (MIDI) Instrument (The L Is Silent)

This project came to me when I saw this contest...4 weeks ago. Blending a sophisticated cello/guitar hybrid with as many otherworldly instrument designs as possible, I was inspired by logarithmic and nautilus spirals, snails, and the possibility to bring many concepts into a 'smart' instrument system. Developed as a deep dive into embedded systems, mechanical torque, and cognitive flow states, my 'Cathedral Snail' features a rotating "Picker Disc," a 144-LED reactive light array, and an integrated 'musical flow states' system featuring different midi/mp3 sounds and effects. I was really blown away by 'feature creep' and by all the work that was required from my ideas...I feel like a mad scientist! This was 100% late night brainstorming sessions, drawings, and extensive use of Autodesk Tinkercad—probably ill advised for this project, but I like the UI. Future iterations will be made, from synth integration(Mozzi synth library) to adding 4 strings that can be manipulated by the joystick, potentiometers and the whammy bar(another potentiometer) as well as funky presets that can be loaded onto the esp32.

Core Processing & Control

1. ESP32-S3 Development Board: Features a Xtensa LX7 32-bit dual-core processor (240MHz) with 8MB internal PSRAM and 16MB external SPI Flash (N16R8).
2. 4 neodymium magnets (salvaged from dead hard drives)
3. 4 6mm buttons (for the dpad)
4. 3 Potentiometers
5. Piezo pickup module
6. Instrument input jack
7. Flatwound Nickel plated(Magnetic) Electric Guitar Strings
8. 500mm Carbon Fiber rod for support
9. 3D Printed/Custom Chassis
10. A 3d printer with Lots of Clear PETG filament (or any of your choosing)
11. An xbox one controller, preferably broken
12. Several 'Arduino/Esp32 Electronics starter kits'
13. A soldering iron
14. Wire stripper
15. Digital Calipers
16. Multimeter
17. Screwdriver + Allen keys
18. Heat set inserts
19. Heat shrink
20. Electrical Tape
21. Small speaker
22. Usbc breakout board
23. ADS1115 ADC Module
24. PCS8574 Expansion Module
25. DFplayer mini Mp3 Module
26. Xbox Rumble Motor, also salvaged
27. S8050 NPN Transistor
28. 1N4001 Flyback Diode
29. Lots of female-to female jumper wires
30. 3.7v lithium battery
31. 3-5v booster module
32. Addressable WS2812B LED Strip
33. Epoxy, Super Glue, Hot Glue and Other Fasteners
34. Patience

The SNAIL with SnailOS is a "Hybrid Chordophone" that draws from several distinct mechanical lineages:

1. The Hurdy-Gurdy (Mechanical Friction): The intention was to replace the hand-cranked resin wheel with an automated, high-torque motor system.
2. The Circle Guitar (Rotary Strumming): A cool new instrument invention is the Circle Guitar, which uses a motorized ring of small pick nodes to 'strum' the guitar at many speeds for rhythmic variation as well as replacing the strumming hand's job entirely. My instrument uses a spinning Picker Disc to achieve "inhuman" strumming speeds (tremolo) as well as neodymium magnets for a creepy 'warble' effect.
3. 'Music-Shaped Objects': I went on a mission to research any and every kind of acoustic or electronic instrument—from the violin and cello to handmade midi instruments, my research sent me to far away lands and designs I didn't know existed. Research into the Hurdy-Gurdy and retro 'synth guitars' informed the "Snail-Vox" and "Synth" states—focusing on drone-based, haunting, and dissonant frequencies rather than standard musical scales.

I initially drew a snail that would have a back-horn speaker effect echoing through the body; but as the thing evolved I realized there's be no room for all the electronics I intended, so I designed something akin to a headless double bass mixed with a les paul the size of a baritone ukulele.

Tinkercad and I go way back. I have learned several engineering-grade CAD softwares, but this one just feels the most intuitive. I am studying cognitive science, so my interest in cognitive load was the basis of my work—how could I make an instrument that took 'thinking' and chord shapes/progressions away from the user's cognitive load, and replaced them with tactile, haptic and visual feedback? The neck is an adaptation of a really cool Printables instrument I also took inspiration from for the scale. I added a rounded nut to accommodate a specialized fretboard: it uses a compound radius like a violin or cello that flattens to a guitar radius, with no frets—the intention is to 'feel' your way around until it's natural muscle memory. To make the body, I took my Frankenstein's monster drawing, made a .png into an .svg and extruded it. I'm really impressed I was able to make the body from a drawing and some shapes. I added a Dpad, a joystick and traditional tone and volume knobs.

The Processor: ESP32-S3 (Xtensa LX7, 240MHz). Crucial for handling the "parallelism" of the UI, motor timing, and I2C/SPI communication.

The Display: 2.8” IPS TFT (ILI9341V). Optimized with lowered 27MHz SPI speed and explicit inversion to prevent ghosting during high-speed UI transitions.

The Logic Expansion: ADS1115 16-bit ADC. Used to bypass the ESP32’s noisy internal ADC for "Studio Grade" joystick precision.

Power Isolation: S8050 NPN Transistor & 1N4001 Flyback Diode. This is the "Power Muscle," allowing the logic pins to control the high-current salvaged Xbox rumble motor.

Visual Feedback: 144 Pixels/m WS2812B Strip. A high-density array used for "Data Visualization" of the music.

Learning Platform.io: I had never used it before this. It's a bit daunting; but against all odds it's very respectable for programming and testing microcontrollers. It has a large library of project examples as well as templates for over 1500 boards.

I also scavenged and took apart any and all electronics I could find to learn about smd level components, motors, pcbs and microsoldering. I thought about adding a vape 'puff sensor' for a flute-like experience—but that's a bit unwieldy on this instrument, so I'm going to make another one(stay tuned).

I had an especially good time picking out ESP32 components and modules that allowed me to expand the use cases—I'm thinking about an IR sensor-enabled pickup and a gyroscope that oscillates the sound like a theremin. There's so many kinds of sensors availible I have multiple instrument ideas in mind that are distinctively unique—and 'weird synth junkie'-esque.

The Theory: Reducing "Cognitive Load"

In music psychology, a "Flow State" is interrupted when a performer has to stop and think about trained muscle memory, chord progressions, finger placement or technology. My UI solves this through:

1. Visual Pacing: The 144-LED strip changes hue and "flow speed" based on the selected instrument, giving the user an extrasensory cue of their current state without needing to look at the screen.
2. Haptics and tactile feedback through the vibration of the speaker and motor, whammy bar, joystick and lights that change color depending on what setting or instrument state you're using.
3. The States:
4. 'Guitarviol': A droning electric guitar-software assisted electric guitar or viola.
5. SYNTH: Drone-based oscillators on a touch screen 'kaos pad'.
6. DRUMS: Drum Pad with customizable presets.
7. SNAIL-VOX: A granular synthesis approach to vocal timbres controlled by touch and the joystick.
8. BASS: Sub-harmonic frequencies designed to vibrate the physical chassis like a larger instrument with sub-octave shifting.

I used Gemini as a backboard for brainstorming, help with wiring things I didn't yet understand, mechanics research and a lot of the code work. I learned a whole lot; I don't think I would have otherwise—the AI was able to sense the directions I was taking myself and offer extensively complex mechanical and electrical techniques (that went over my head) that I used to make step-by-step instructions and guides for myself to push on. There was obviously a lot of frustration using ai as a lab partner—namely that it 'forgets' and 'hallucinates' information--about 6 times I threw up my hands as it completely broke my script—but all in all I think the future of AI rests in the hands of a human creator's brain, ingenuity and creativity; and now there are no boundaries keeping me from taking on an enormous challenge.

Technical Lessons Learned:

Building the Cyber-Snail was a masterclass in the difference between a Tinkercad simulation, a silly idea and physical hardware implementation. Below are the three most significant technical hurdles I cleared.

1. High-Current Load Management (The Motor)

The Failure: Initially, I attempted to drive the salvaged Xbox rumble motor directly from an ESP32 GPIO pin. The motor wouldn't budge, and the ESP32 began to heat up. I built and rebuilt the picker disc but had trouble getting the torque needed to really 'spin' the disc at a playable level as it was heavy with the magnets. I definitely think recycling was more fun, but in the future I would use the appropriate components for a stable and easier build. I learned that Microcontrollers are "brains," not "muscles." An ESP32 pin can only provide ~40mA, but a stalled DC motor can demand upwards of 500mA. The Fix: I implemented an S8050 NPN Transistor switching circuit. This allowed the ESP32 to act as a gatekeeper, using a tiny signal to "unleash" the full current of the 5V power hub directly to the motor. Thanks, Ai.

2. Protecting Logic from Back-EMF

The Failure: Every time the motor turned off, the ESP32 would mysteriously reset or the ILI9341 screen would flicker and freeze. It took ages for me to get a stable build and upload(using Platform.io and several arduino libraries) I learned of "Flyback Voltage." When a motor's magnetic field collapses, it sends a high-voltage spike back into the circuit. Certain configurations would dim the lights and silence the speaker if I pulled too much current. The Fix: I added a 1N4001 Diode in parallel with the motor. This "Flyback Diode" provides a safe path for that energy to dissipate, acting as a one-way valve that protects my sensitive logic components. I bit off way more than I could chew in my understanding of what connects to where, and how many things can go wrong in between. I'm just happy I didn't short anything!

3. I2C Bus Stability & Precision

The Failure: The joystick values were "jittery," causing the Snail OS to scroll randomly between instruments (Piano, Synth, etc.). The touch screen also took forever to code correctly; Platformio insisted my PSRAM didn't exist, breaking things repeatedly as I tested hardware. I didn't expect the Xbox joystick to work at all, but it did, and I was able to get at least working feedback that the joystick was sensed by the system.

The Lesson: The ESP32’s internal ADC (Analog-to-Digital Converter) is notoriously noisy, especially when WiFi and Bluetooth are active. I needed converters and shielding as well as careful multimeter continuity and voltage testing components one by one to build a working and static-free prototype for audio production.

The Fix: I integrated a dedicated ADS1115 16-bit ADC via the I2C bus. By offloading the analog reading to a specialized chip, I achieved 16-bit precision, which I then refined with a software deadzone to ensure the UI only moves when I intend it to. The touchscreen is now 'native' and natural, and you can swipe between different 'states' like an iphone glued to a guitar.

All in all I've had a ton of fun, and was able to make this in 4 short weeks. I will continue building upon my design in future iterations and am excited to get to playing every instrument under the sun on one device.