Browse Prior Art Database

Multiperson Sensor

IP.com Disclosure Number: IPCOM000051292D
Original Publication Date: 1981-Jan-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 59K

Publishing Venue

IBM

Related People

Dillon, BC: AUTHOR

Abstract

Access to secure areas can be controlled by badge readers which only open a door if an authorized badge is inserted. However, once the door is opened, any number of people can enter the secure area without inserting their own badge into the badge reader. To insure that each person entering the secure area inserts his badge, three sonic sensors, triangularly positioned, as shown in Fig. 1, are used.

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Multiperson Sensor

Access to secure areas can be controlled by badge readers which only open a door if an authorized badge is inserted. However, once the door is opened, any number of people can enter the secure area without inserting their own badge into the badge reader. To insure that each person entering the secure area inserts his badge, three sonic sensors, triangularly positioned, as shown in Fig. 1, are used.

The sonic sensor approach is based on using three sensors in a triangulated area for sensing the distances to the various targets or objects in the target triangle. Thus, at least one of the sensors will detect multiple objects in the area.

When a badge is read, a computer begins to monitor the sonic sensors for multitargets passing through the target area. Thus, one badge read equals one target, and so forth. One read and two targets is an indication of an entrance without properly inserting a badge.

Figs. 1 and 2 show a typical monitoring station having three sensors A, B and C protecting a badge reader access door. Fig. 3 shows a block diagram of the sonic sensor system. The transmitting and receiving transducers are physically placed side by side, and they can be controlled by either a computer or a proximity switch, or they may be free running. The clock and timing generator supply a series of pulses to gate and control the three transmitting and receiving stations A-B-C.

A transmit pulse is applied to the transducer which sends out a resonance ...