Electrical Arc Speaker (EAS)

Spring 2025

The Electric Arc Speaker (EAS) utilizes high voltages to manipulate an electrical arc, creating sound waves from plasma. Our main goal for the electric arc speaker is to inspire and impress users and observers of our project. In order to accomplish this goal we set out a couple of requirements that our system must meet. This includes, but is not limited to, having audio that is audible and can span over a frequency range of at least 500-1000Hz, include a form of signal input (wired 3.5mm connection) between the user and the system that can allow the user to directly change the audio being output from the system, and showcasing the plasma arc that our system creates. We believe that these requirements have helped us create a project that can achieve our goal as good audio quality displays that our system works well, the intractability with the system helps users get involved, and the plasma arc is a visual representation of the system in action. In addition to the requirements for our system to be as awe inspiring as possible we are also defining some requirements to ensure the safety of the users and observers of our system. In order to meet these requirements we researched different technologies already available, such as per-existing similar projects, signal-injection techniques, high-voltage safety procedures, MOSFET amplification, and flyback transformer operation. Through this research, we were able to create a system that met nearly all of our system requirements. Along the way, we ran into several obstacles that have offered us valuable insight into things that we would change about our design in the future. First, our PCB design has traces that are only rated to 7A. When we were in the design stages this did not seem to be an issue, however when we put everything together with the PCB we quickly realized that in order for the sound to be louder and clearer we would need far more than the 7A we were capped at. We made the decision to operate at a lower amperage and take the loss in sound simply for the safety of the system and the user. Second, our signal-injection method (what allows us to inject an audio signal into the flyback transformer, and ultimately allows for sound to be heard across the plasma arc) uses a 555-timer-based topology. While this did end up working, we believe that using a dedicated flyback driver (such as the TL494) or using a Pulse Width Modulator IC (such as the SG3525A) would have led to a more stable and frequency-flexible design. Ultimately, this project provided our team an excellent opportunity to get hands on experience with high-voltage components, experiment with complex signal-processing techniques, and to develop a better understanding of the engineering design process.

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Artifacts

Name Description
System Input Requirement Video demonstrating that the "System Input" Engineering Requirement was met (User Test)   Link
Quality of Sound Requirement Video demonstrating that the "Quality of Sound" Engineering Requirement was met (User Test)   Link
East of Use Requirement Video demonstrating that the "Ease of Use" Engineering Requirement was met (User Test)   Link
Produces Plasma Requirement Video demonstrating that the "Produces Plasma" Engineering Requirement was met (User Test)   Link
KiCad PCB Design - Electrical Arc Speaker KiCad project archive for the Electrical Arc Speaker PCB   Link
Bill of Materials Bill of Materials for Electrical Arc Speaker PCB   Link
Initial Research Documentation Initial research documentation containing information we gathered at the start of the project design phase   Link
Project Document - Team 18 (Electrical Arc Speaker) Project Document for Team 18 - Electrical Arc Speaker   Link
Arduino Code - Fan PWM and TempSense Logic Arduino Code for the Fan PWM generation and the Temperature Sensor Logic (LM75A-based); must use Arduino R4 Uno WiFi in order for LED Matrix to work   Link
Project Summary Video Video that goes over our project design, achievements, challenges, and takeaways.   Link
Project Poster Poster used in OSU's 2025 Engineering Expo providing readers with an introduction to the group members and the project itself.   Download
Project Document In depth documentation for our project.   Download
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