Garmin Tone Generator
The Garmin Tone Generator was a semester-long project that I completed with a team of four other students. We were approached by a mechanical engineer at Garmin and tasked with developing a wrist-mountable testing device that could project sounds generated in real time and allow divers to provide immediate feedback to engineers above the water, reducing the overall testing time.
Motivation
Free divers swim hundreds of feet underwater without any breathing aids, relying on auditory tones from dive watches to monitor their physiological parameters and time key moments during their dive, such as when to begin their ascent. Garmin’s existing tone testing process was inefficient: divers listened to multiple tones, one after another, and would have to remember which they liked best, having to return to the surface to give feedback.Design
Over three months, we brainstormed, prototyped, tested, and iterated until we reached a final design. The housing was 3D-printed out of PLA and featured a silicone watch band, making it adjustable for a wide range of wrist sizes. A speaker was adhered on top of the housing, capable of playing tones from 200Hz to 19kHz. A sound engineer above the water would send a tone from their computer to an amplifier via a Python script. The amplified signal was then transmitted to the underwater speaker. Each tone was followed by a dial tone, prompting the diver to provide feedback. The tones were rated on a four-level subjective scale (bad, good, better, best) using a potentiometer, chosen for its ease of waterproofing compared to traditional buttons. Finally, the potentiometer reading was sent to an Arduino where the feedback was processed and logged into a text file for data analysis.
Challenges
The main challenge during this project was waterproofing the potentiometer. We sealed it with epoxy and conducted durability testing by submerging two potentiometers in freshwater and saltwater for three weeks. While the fresh water potentiometer performed as expected, the saltwater potentiometer experienced fluctuations that limited its response range. With additional time, we would have worked to improve performance in saltwater environments to ensure reliability across all conditions.
