An Ultra-Low Power, Optically-Interrogated Smart Tagging and Identification System

We present a wireless identification system that employs an optical communications link between an array of uniquely identifiable smart tags and an interrogator flashlight. As the tags consume a quiescent current of under 2 microamperes and are woken up directly by the interrogator’s modulated illumination, they are able to last nearly the shelf life of their battery with moderate use. Unlike RFID, which requires a large antenna to achieve significant range, our system requires only a small photodiode, which enables very compact tags to be rapidly queried at a range of over 8 meters with a handheld flashlight interrogator. Our tags are currently aimed at an asset location scenario, where they pulse an onboard LED when their stored ID matches a query broadcast by the interrogator. We also present two different techniques that allow the tags to talk back to the interrogator – one that uses an onboard IR LED to send data a meter away when the interrogator illumination is off and anot...

• Type: Conference
• Year: 2005
• Where: AUTOID
• Authors: Gerardo Barroeta Perez, Mateusz Malinowski, Joseph A. Paradiso
• Keywords: AUTOID 2005, Interrogator Flashlight, Interrogator’s Modulated Illumination, Pattern Recognition, Tags