The thermometer is one of science’s most iconic measurement tools, but, even as tubes of mercury and alcohol made way for digital equivalents, they all lacked a common, sought-after feature. Taking a person’s temperature at a single point is increasingly simple, but using the same technology to continuously monitor that temperature remains a challenge.

Enter Fever Smart, a digital thermometer that is applied like a Band-Aid under a patient’s arm and wirelessly feeds temperature to a smartphone.

It is the brainchild of recent Penn graduates Aaron Goldstein, an economics major with a finance concentration in the Wharton School, and William Duckworth, a mechanical engineering and applied mechanics major in the School of Engineering and Applied Science. They are two of the four winners of the inaugural President’s Innovation Prize.

Goldstein, from West Palm Beach, Fla., and Duckworth, from Lake Forest, Ill., were neighbors in the Quad their first year, but it was another mutual friend who first inspired the idea that made them business partners.

Collin Hill, a Wharton senior, had been recently diagnosed with cancer and was being treated while at school. Patients undergoing chemotherapy have suppressed immune systems and must keep watch for signs of an infection, such as a fever.

“Collin was constantly taking his temperature to make sure he didn’t have an infection,” Goldstein says. “Most of the time he was fine, but there were a couple of instances where he would have a normal temperature, go to sleep, then wake up five hours later with a 105-degree fever and have to go to the hospital.

“Talking to Collin, you could tell he was really frustrated by not being able to continuously monitor his temperature and getting an alert when it started to rise.”

Goldstein and Hill launched a crowd-funding campaign for the device that would eventually become Fever Smart in the fall of 2014, raising more than $65,000. They soon brought on Duckworth for his technical expertise, as well as Goldstein’s older sister, Becca, a fellow Wharton student, to help run their nascent business.

Fever Smart also enlisted Matthew Grennan, an assistant professor of health-care management at Wharton and a Senior Fellow at Penn’s Leonard Davis Institute of Health Economics. He will serve as the team’s faculty advisor.

The Fever Smart team reached out to Grennan, who teaches a class on health-care entrepreneurship, to help navigate the shifting landscape of markets for medical devices and services. Focus groups and feedback from their first commercial customers has pointed them in several promising directions. Getting Fever Smart into hospitals and other clinical settings is the team’s next big goal.

“That’s what surprised me most on the technological side,” Duckworth says. “You can take a few simple components, put them together and have a million people say, ‘Oh, my god, we’ve been waiting for this.’”