Steth IO Steth IO
industrial design
color, materials, finish
mechanical engineering

Steth IO

Medical Innovation
industrial design
color, materials, finish
mechanical engineering

Steth IO is a smartphone-powered stethoscope that captures heart and lung sounds and converts them into a spectrogram, a visual representation of sound frequencies. The hardware resides in a smartphone case that modernizes centuries old stethoscope technology into a handheld device.

It was invented by 15-year-old Suman Mulumudi and his father, cardiologist Mahesh Mulumudi, founders of Seattle-based medical device development company StratoScientific Inc. Steth IO is a 2018 IDEA Award Finalist.

with Heart

StratoScientific approached Tactile to help bring their concept architecture to product development. We helped navigate the refinement process, which included design, CMF work, and coordinating the tooling and manufacturing processes. The aesthetics of the case needed to reflect the quality, abilities, and sophistication of the powerful medical device.

Material Choices

We made sure it was easy to insert and remove a phone from the case, testing the effect of different materials on critical acoustics, and minimizing part count. We discussed manufacturing techniques early on, which meant by the time we started manufacturing, we didn’t have to compromise the design because we already knew what kinds of materials were possible and what wasn’t.

The medical environment uses harsh chemicals and cleaners to wipe down devices, which was also an important consideration in choosing materials.


Sound quality is imperative to the function of the device, which works by routing heart and lung sounds 180°. Our engineers helped determined how to best manufacture Steth IO, with high priority given to non-negotiable factors, like audio, performance, and client need.

We asked questions like: Which hand would the doctor use to hold the device? Would they use both hands? Are their elbows typically sticking out or tucked in?

Iterative Future

The iPhone 6 will be the Steth IO’s flagship phone case, with update potential for future phone releases. Our input set the tone for the current and all future iterations of the device. For the first time, the stethoscope would be able to progress in form and function alongside emerging technology.

The result of our collaboration is a truly groundbreaking device. The stethoscope is perhaps the most ubiquitous and essential medical device built in the 21st century and we’ve taken it even further.