MAE 151B: E-SONIC Bubble Box

Summary

Bubble Box is an interactive musical instrument that turns visible fluid motion into sound. The project was developed for the E-SONIC new instrument competition, where engineering design is used to create original instruments that are playable, expressive, and visually engaging. Bubble Box addresses the challenge of making a fluid-based instrument that is not only interesting to watch, but also repeatable enough for a performer to control during a live demonstration.

The final design uses water pulses to generate vortex rings inside a transparent chamber. These vortex rings travel through the water and perturb a flexible membrane connected to a sensor. The sensor signal is processed by an Arduino-based electronics system and converted into musical notes. The result is an instrument where the performer can “play” vortex rings, creating a direct connection between fluid motion, visual rhythm, and sound.

Technical Approach/Methodology

The design combines fluid mechanics, mechanical actuation, sensing, electronics, and musical output into one integrated system. A bellows-driven actuation system sends pressure pulses through tubing to a piston mechanism, which displaces water through a fixed orifice to generate vortex-ring motion. The water chamber was sized and arranged to make the vortex motion visible while keeping the system compact enough for a tabletop demonstration.

A flexible membrane was placed in line with the vortex path so that the water motion could be detected mechanically. Sensor signals from the membrane are read by an Arduino, which maps each input to a musical note. The prototype was also programmed with multiple song modes, including recognizable demonstration sequences such as Jaws, SpongeBob, and Blinding Lights. The final system integrates the mechanical water chamber, pneumatic actuation, membrane-based sensing, microcontroller logic, and speaker output into a playable prototype.

Testing focused on whether the actuation system could generate strong enough water motion to consistently activate the sensor, whether the sensor response could be converted into clean musical notes, and whether the full assembly could operate safely with water and electronics in close proximity. The design process included CAD modeling, prototype fabrication, fluid-dynamic analysis, electronics testing, Arduino programming, leak-risk reduction, and full-system integration.

Outcomes

The team produced a functional Bubble Box prototype that demonstrates a new way to turn vortex-ring motion into sound. The final instrument includes a transparent water chamber, bellows-based actuation system, piston and orifice assembly, membrane sensor interface, Arduino-controlled audio output, and multiple playable song modes. The prototype successfully connects a physical water disturbance to an electronic sound response, allowing the performer to create music through controlled fluid motion.

Major deliverables include the final integrated prototype, CAD and fabrication documentation, engineering analysis of the actuation and vortex-generation system, electronics and Arduino code, bill of materials, risk and safety review, validation testing, final design binder, poster, and presentation materials. The project shows how mechanical design and fluid dynamics can be used creatively to produce an expressive instrument that is both visual and interactive.

Project Media

Project Video

Project Poster