One night in late 2009, Ming-Zher Poh and his roommate, Dan McDuff, asked some friends to sit in front of a laptop. Poh, an electrical- and medical-engineering graduate student at the Massachusetts Institute of Technology, was trying to transform the computer’s webcam into a heart-rate monitor. He hoped that his software would allow doctors to check the vital signs of burn victims or babies without attaching uncomfortable clips, and that it would make it easier for adults to track their cardiovascular health over time. That night, the program wasn’t working in real time, but its measurements were near perfect. “Right away I knew we had something special,” Poh says.
A year and a half later, a large framed mirror embedded with a more refined version of Poh’s system sits in the MIT Media Lab. Behind the two-way glass, a webcam-equipped monitor is wired to a laptop. Stand before the mirror, and the otherwise blank monitor projects your heart rate on top of your reflection.
When your heart beats, it sends a pulse of blood through your blood vessels. Blood absorbs light, so when more of it travels through the vessels, less of the light hitting your skin is reflected. A webcam can pick up those small fluctuations in reflected light, Poh says, and a computer program can translate that data into a heart-rate reading.
Poh plans to try to bring the mirror to market after he finishes his Ph.D. later this year. He says the system could be used to measure other vitals as well, including respiratory rate and blood-oxygen saturation, which should broaden its appeal. “This shows your inner health,” he says. “Maybe as people use it, they’ll say, ‘This is part of my identity. It’s not just how I look on the outside.’"
Name: Medical Mirror
Inventor: Ming-Zher Poh
Time: 1½ years
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.