Figuring out who’s taking their pills is about to get easier. The U.S. Food and Drug Administration approved a “smart pill” that can tell whether a medication has been taken as prescribed.

Made by Proteus Digital Health, the small pill is made primarily of silicon and embedded with a microchip sensor. When activated by stomach acid, the sensor transmits a signal to a skin patch that indicates a medication has been swallowed. The patch sends the information to a smartphone app, along with the wearer’s heart rate, temperature, and activity level.