ActiveBadge:1 WirelessNet Tseng The Active Badge Location System R. Want, A. Hopper, V. Falcao, and J. Gibbon in ACM Trans. on Information Systems, Vol. 10, No. 1, Jan. 1992, pp presented by Yu-Chee Tseng --

ActiveBadge:2 WirelessNet Tseng How Do We Locate People?  Goal: efficient location and coordination of staff in a large organization. Ex: location of doctors, staffs, and patients in a hospital.  Existing Solutions: broadcasting a phone to call several possible numbers a beeper with audible signal or call-back number key card ( 刷卡驗證 ) for access control:

ActiveBadge:3 WirelessNet Tseng Active Badge System  each badge that can automatically emit a unique code  a network of sensors placed around the building  a master server, also connected to the network, makes the location information available to outside world Active Badge... Active Badge Badge Sensor Server/Application network wireless IR

ActiveBadge:4 WirelessNet Tseng Active Badge Design (cont.)  Pulse-width modulated infrared (IR) signaling: transmission range: 6 meters can reflect by office partitions, but will not penetrate like radio signals  emits a unique code every 15 sec, for about 1/10 sec. Quite power-saving. Can last for > 1 year. Has a light detector. On dark (e.g., badge placed in a drawer), increase emitting period. Can last for > 4 years.  Good performance to wear on breast pocket; OK to wear on belt or waist.

ActiveBadge:5 WirelessNet Tseng Badge Sensor and Networking  many sensors can be installed, as the unit cost is very low. can be placed on walls, entrances, exits, corridors, public areas, etc.  sensor ---(RS232)---> computer ---(Ethernet)--> server up to 128 sensors can be supported by a computer a FIFO buffer can store 20 badge data items (to avoid network congestion)  sensor networking: 4 wires (2 for power supply, 1for control/poll, and 1 for data) conform to telephone cabling, thus easy for cabling and low- cost

ActiveBadge:6 WirelessNet Tseng Badge Sensor and Networking (cont.) fig. 2

ActiveBadge:7 WirelessNet Tseng Application: Active Office  a system integrating name location information phone network  commands supported: FIND (name) WITH (name): who are the other badges nearby name now LOOK (location) NOTIFY (name) HISTORY (name)

ActiveBadge:8 WirelessNet Tseng Active Office Display Screen Fig. 3

ActiveBadge:9 WirelessNet Tseng Benefits of Active Office  automatic re-direction of incoming calls relieve burden of receptionist you have less chance of missing some important calls you are waiting for  receptionist can easily tell whether a person is in or not  easier when calling for a meeting  easy to identify visitors to our organization

ActiveBadge:10 WirelessNet Tseng Conclusions  Future: extend to 2-way communication  Future: combine with motion detector can provide high security if a person moves without active badge being detected, an alarm can be alerted.  Mobile 911 (emergency call)