Tiny ingestible robot could work wonders inside you

It's a little known but often dangerous problem: each year, 3,500 people in the U.S. -- mostly young children -- swallow button batteries. Normally, these batteries pass through the body without incident. But if they come into prolonged contact with esophagus or stomach tissue, the results can be harmful: the batteries can cause an electric current that produces hydroxide, which burns through body tissue. A postdoctoral student at the Massachusetts Institute of Technology, Shuhei Miyashita brought up this hazard to Daniela Rus, the professor who leads the Computer Science and Artificial Intelligence Laboratory. A simple experiment proved how hazardous the little batteries can be.