A Penn State researcher has shown a prototype glucose sensor that is very tiny and is inserted under the skin. The device registers the patient’s glucose level when an external unit passes a magnetic field over the spot of the inserted sensor. The external detector is currently the size of a mobile phone but the creators believe it could eventually be packaged as a much smaller unit for portability. The sensor was developed by Craig A. Grimes, professor of electrical engineering and materials science and enginering at Penn State. No word on when this sensor may find its way to diabetic patients.