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The Active Badge System


The Active Badge system provides a means of locating individuals within a building by determining the location of their Active Badge. This small device worn by personnel transmits a unique infra-red signal every 10 seconds. Each office within a building is equipped with one or more networked sensors which detect these transmissions. The location of the badge (and hence its wearer) can thus be determined on the basis of information provided by these sensors.

This page describes the deployment of Active Badge research prototypes.

Over 1500 badges and 2000 sensors are deployed throughout a number of European universities including the University of Kent, Imperial College, London, Lancaster University, and the University of Twente, Netherlands. In the USA, Xerox PARC, DEC research laboratories, Bellcore and MIT Media Lab have all received Active Badge systems.

The largest single system is at Cambridge University Computer Laboratory , where over 200 badges and 300 sensors are in daily use. Information about the location of individuals is also exchanged between these sites where appropriate.

Information about the location of individuals is made available through the WWW Active Badge Service. This Global Communication Service offers a way of determining the most appropriate means of contacting an individual.


The Active Badge was conceived, designed and prototyped between 1989 and 1992. In its original form, the badge transmitted a unique five-bit code every fifteen seconds. Successive versions have expanded the functionality and address-space size of the badge. The current version of the badge incorporates a small microprocessor, offering bi-directional communication, and a 48 bit address.

At various times Andy Hopper, Roy Want, Andy Harter, Tom Blackie, Mark Chopping, Damian Gilmurray, and Frazer Bennett have all made a contribution to the development of the Badge and the supporting software.


Investigation into mobility and location technology continues, and the Active Badge has become a cornerpiece to this research. A simpler version of the Active Badge has been designed for tagging equipment, and location to the desk-scale, rather than the office-scale, is achieved in experiments using low-powered radio fields.


The Active Badge system has received much publicity and has been widely written about. Our technical reports and papers describe the systems that we have developed to support Active Badge technology as well as providing a more general overview of the technology . Other technical documentation describes the protocols used within the Infra-Red network . Active Badges have even featured in a cartoon in a national newspaper!

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