1. 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. 91-102 -- presented by Yu-Chee Tseng --

2. 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:

3. 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

4. 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.

5. 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

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

7. 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)

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

9. 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

10. 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)