Brothers Jaiden and Deven Reddy were tired of seeing their friends vaping. At their Las Vegas, Nevada, school, students sneak e-cigarettes in the bathrooms and the halls, they say. Teens do it at other schools too. U.S. data show that nearly 40 percent of 12th-graders vaped nicotine in 2018. Nicotine is highly addictive and can impair memory.

So the brothers teamed up with three of their friendsalso brothersto invent VapeMate, a device that can be attached to an e-cigarette to track nicotine intake. A linked app can then shut off the vape at a preset limit. This can help users quit vaping over time

The group won a top prize last spring in the Conrad Challenge, an international STEM competition. They hope to get VapeMate on the market someday soon. “We have lots of friends who are addicted to vaping,” Jaiden explains. “It has become a really big problem.”