Seven years after the digital respiratory startup Propeller Health launched, co-founder and chief technology officer Greg Tracy told a crowd at this year’s Medical Sensors Design Conference that what started as an attempt to build sensors for respiratory devices has slowly evolved into a “hardware-enabled software company.”

“We thought that we were going to go build devices and drop this magical things in patients’ lives and they were going to get better,” he said. “And we were wrong about that. It turns out that onboarding people and injecting technology into their life isn’t like throwing pixie dust. It’s actually very hard.”

But after an intentional shift in focus, the Madison, Wis.-based company has learned a lot about developing connected respiratory devices and using that data in a way that serves their patients.

“We’ve built the world’s best analytics engine for respiratory patients,” he said.

Propeller partners with pharmaceutical companies, including Novartis and GlaxoSmithKline, to connect its sensors to inhalers for patients with asthma or chronic obstructive pulmonary disease. The company has learned that pharmaceutical companies are generally happy with how effective their drugs are – but they can’t get patients to comply to prescribed regimens.

Digital health has been touted as a way to boost patient compliance, but Tracy said Propeller quickly learned how tricky it can be to get patients to adopt new technology.

“The number one lesson here is don’t add a new burden,” he said. “It’s important to have a lot of empathy here that people with chronic illnesses are struggling. So if you’re going to inject technology into their life, you have to make it easier for them.”

Tracy added that the experience needs to be passive for the patient, otherwise they are likely to stop using the device.

“They’ve got to just pull it out of the box, get [the sensor] on their meds and that should be the only thing they have to do,” Tracy said. “Don’t make them change the way they use their meds. Eliminate cables. No charging. No syncing. Just make it work.”

Propeller uses a variety of sensors to detect when people are and aren’t using their prescribed medications. The company intentionally designed its device to use as little power as possible.

“We need to know when they breathe. We need to know when they inhale, but that microphone is really power-hungry, so let’s not turn on the microphone until we know they’re about to inhale. So how do you do that? Well, you put a little capacitive touch on the rim and you wait for their lips to come up to the device. And once you do that, now it’s time to turn on that mic,” Tracy explained.

But capacitive touch isn’t cheap, either. So to trigger that sensor, the company uses an accelerometer to know when the patient moves the device. All of these sensors help Propeller efficiently manage their “power budget,” so patients aren’t constantly recharging their devices.

“This is the jungle of real consumer life,” Tracy said. “It doesn’t matter how fancy, how awesome that engineering and technology is underneath. If you can’t get people in their busy daily lives to do what you think might be a simple task, it will turn out to be a hard task. Then you’ve lost them.”

Tracking symptoms and medication use isn’t a new concept – many asthma patients are asked to keep track of these things using a paper-based logging system. But, as Tracy points out, that system is hardly flawless.

“Patients are notorious for sitting in the parking lot, 30 minutes before their appointment and frantically filling out their log,” he said. “You don’t want to replace the log. You want to automate the log.”

Beyond automating the experiences that asthma patients are familiar with, Tracy said Propeller is trying to create new experiences. The company is experimenting with tracking weather patterns while patients use their medications to better understand what triggers an exacerbation of symptoms. Then, the app provides a personalized forecast for the next day based on air quality, humidity and other parameters.

“It’s the small data that makes it the most meaningful, because it’s a highly personalized experience,” Tracy said. “The disease itself is very personalized, so we do our job when we’re very unique and personal to you as an individual patient.”

Propeller adds to the personalized experience by reminding you to take your medication and turning off the reminder if it senses you’ve already taken it. Tracy said the company hopes to one day be integrated into even more aspects of a patient’s daily life.

“If you’re on Google Maps and you’re looking for a restaurant, we should also tell you where you’ve struggled in the past. If we know from your Google Calendar that you’re traveling to Boston next week, we should give you an asthma forecast in Boston, not in Madison,” he said. “It should just be ambient. It should be wherever you are.”

Tracy acknowledged that patients have to be willing to disclose an array of personal information to use Propeller-enabled devices, but he said that knowing a lot about individual patients is how they help patients get better.

“You’re going to tell us a lot about yourself and we’re going to track you. The commitment we make to you is we’re going to keep your data private. We’re not going to sell your data. We’re not going to give direct access to your employer for that data and other people,” he said. “And hopefully when you tell us so many unique things about yourself, we’re going to actually deliver for you.”