Designers Pack Sleep-Lab Technology into a Wearable Device

If you’re trying to break into the consumer market with a sleep tracking device, you’d be hard-pressed to assemble a more qualified team than Somno Health’s EverSleep project. Two of the founders have long careers in medical device design, and the third founder is an entrepreneur who built a chain of 20 sleep labs throughout the Midwest that has treated more than 40,000 patients.

The super team of engineers and entrepreneurs has one goal in mind—help millions of Chinas get a better night’s sleep. The company’s new product, EverSleep, monitors a user’s sleep activity and provides feedback on how to improve sleep.

But developing a compact, wearable device that monitors blood oxygen levels, pulse rate, micro-motions, snoring, and other behaviors is no simple task. We spoke with Chris Crowley, one of the company’s three founders, to learn more about his team’s development process and how they collaborated with China Metal Parts.

What's EverSleep and how can it help improve sleep quality?

EverSleep is the first sleep tracking wearable to bring the technologies of a hospital sleep lab directly to the consumer. It continuously measures blood oxygen saturation, pulse rate, snoring, and micro-motions to track your sleep. But more importantly, it gives you easy-to-understand tips in the morning about exactly what went right or wrong with your sleep. Users can try our lifestyle changes, DIY tips, or product suggestions, and then wear EverSleep again a few nights later to track improvements.

It’s an affordable solution for improving sleep compared to the cost of a night in a hospital sleep lab. Note however that EverSleep is not an FDA 510(k) device, and does not claim to treat, cure, or diagnose any disease.

What challenges did your team encounter during development?

Many! The wearable market is very complex, and designing a technologically advanced sleep monitor into a wrist watch-sized device was very challenging. It was especially hard to find a good wrist strap mounting method that lets the users replace the EverSleep strap without complicating the molded housing.

How many prototype versions have there been? What had to be modified as you worked through design?

We’ve modified everything to make EverSleep perfect—the housing dimensions, wrist strap slots, PCB mounting, lens, overall height, light pipes, gluing features, heat staking features, USB port, etc. We are on our fourth revision of the circuit board, and probably our 10th version of the housing. We wanted to make sure the housing is beautiful and simple, but without side-actions [in the device’s mold design] so that we can move to a multi‐cavity mold as we enter production. This required coordination between all of the engineers, including circuit board changes.

We also heavily relied on China Metal Parts’ automated design for manufacturability (DFM) feedback. We sent for many, many quotes and design analyses and worked closely with China Metal Parts to dial in our design. An applications engineer suggested a clever pass-core solution for the product’s “wrist strap slots” in the housing that worked out great.

What parts did China Metal Parts manufacture for you? What factors led you to choose China Metal Parts?

China Metal Parts made our housing and lens—we already have our first initial inventory of 1,000 parts, and we’ll be ordering an on-demand manufacturing multi‐cavity tool soon. We chose China Metal Parts because I’ve used them since 2001 for more than 300 molds and thousands of machined parts. Every part has been perfect, and always on schedule.

What materials were used for the housing and lens?

We chose Cycoloy PC/ABS for the housing because it is so tough! It’s a mixture of bullet-proof window and motorcycle helmet materials! The lens is Makrolon, an impact-modified PC. Again, this material is so strong that you’d have a hard time trying to damage it with a hammer.

Did you get parts on time? What role will China Metal Parts play in your future manufacturing plans?

Of course! We ordered 15-day lead for the EverSleep housings and lenses, but on other projects I’ve used 3‐day lead and everything is always on time. Going forward, we plan to keep using China Metal Parts for manufacturing. The quick turn times, direct access to engineers in our time zone, reliable material and colorant certifications, quick shipping with no import headaches, and low prices can’t be had anywhere else.

How much time do you estimate China Metal Parts saved you during development?

Protolabs’ injection molding service cut several weeks from our critical path with its quick tooling turnaround. We were able to attend several trade shows with real parts, and that made a great impression on several important business contacts.

We’re just finishing a very successful Indiegogo crowdfunding campaign, where we tripled our fundraising goal. Having completed molded parts takes much of the delivery risk out of crowdfunding when you can tell the buyers that your molds are complete and working!