She designed a pregnancy test a blind woman reads

A master's student at Carnegie Mellon University has designed a pregnancy test that a blind woman can read with her tongue. Sneha Rao, 27, calls it Tact: a flat, oval lollipop made mostly of gelatin. If the body is producing hCG, the hormone of early pregnancy, both sides of the lollipop swell into raised bumps. Swelling on one side only means negative. No swelling means try again. Nearly nine million people in the United States live with a vision disability, and most blind women cannot read a standard test because results rely on faint lines and color changes. Rao rejected an app-based version early, because photographing a test leaves a record. "The whole point of Tact is that there's no trace," she says. The device dissolves after use, an idea her advisor traced to spy gadgets built to self-destruct. It is still a prototype. Rao is now working on the DNA that makes the lollipop feel anything at all.