Penn State University researchers have developed a wearable sensor device that can be applied directly to an individual's skin in order to measure his or her conditions, including temperature, heart rate and blood-oxygen levels. The device is designed to be applied directly to a person's body like a temporary tattoo, and with a small wireless module leveraging Near Field Communication (NFC) RFID technology or inductive coupling, it can transmit data to a user's smartphone. Hear how the team has developed a prototype and how the sensors might be used in the future.