EL 10 - S.W.I.M: A Real-Time Audio Waveform Display System

The Sequential Wave Imprinting Machine (S.W.I.M) is a real-time audio visualization platform designed to transform audio signals into dynamic, physical representations of sound. Our project combines embedded systems, motion control, signal processing, and interactive display design into a cohesive and visually engaging machine. At its core, S.W.I.M is a horizontal single-axis gantry system equipped with a high-density RGB LED strip that moves in synchronization with an incoming audio waveform — creating a moving, light-based “printout” of live sound.

This Design offers a wide range of practical benefits and educational value, both in terms of technical skills development and real-world applications. Firstly, it would help the audience to visually understand how sound waves behave over time, aiding hands-on experience with dual-core microcontroller programming. Additionally, it can be used in classrooms, fairs, and workshops to demonstrate signal processing, sound visualization, and electronics. Lastly, integrates knowledge from electronics, mechanical engineering, signal processing, and software development.

The mechanical system of this design includes a 20X40 V-slot liner rail with a belt-driven actuator powered by a NEMA 17 stepper motor and a DRV8825 driver. The motor moves the LED strip smoothly along the rail while audio waveforms are displayed as dynamically changing brightness patterns, producing an eye-catching visual representation of sound.

S.W.I.M brings sound to life in a tangible, real-time form. Here's how the system works:

1. Audio Capture: A microphone or line-in audio signal is fed into the stationary board. The signal is pre-amplified and conditioned for analog-to-digital conversion.

2. Dual-Core Processing: The RP2040 microcontroller uses its dual cores to manage tasks efficiently:

• Core 1 is dedicated to audio processing. It captures ADC data continuously, tracks min/max values of the waveform, and calculates dynamic amplitude.
• Core 0 handles motion and visualization. It receives synchronization events and updates the LED strip and gantry motor accordingly.

3. Waveform Display: The LED strip reflects the waveform in real-time. Aliased brightness gives adjacent LEDs a fading glow, simulating the shape and energy of the audio wave.

4. Motion Control: The gantry moves back and forth using precise motor control. Magnetic limit switches placed at either end of the rail trigger direction reversal, allowing the LED to sweep in a continuous loop — mimicking how traditional oscilloscopes “print” waves on a screen.

This results in a vibrant, physical, and highly engaging display of audio, visible to all viewers, whether technically inclined or not.

The idea behind S.W.I.M stems from our desire to physically visualize sound. While sound is an integral part of communication and music, it is invisible by nature. Usually, waveforms are noticeable through scopes and screens, but we wanted to make it more tangible, dynamic, and educational, something that can be observed, interacted with, and appreciated in real space.

S.W.I.M. isn’t just a machine, it’s an experience. Whether it's music playing or a person speaking into a microphone, the system responds instantly, transforming sound into a mesmerizing dance of light and motion. It serves both technical demonstration and visual art installation purposes.