NCJ Number
106403
Journal
Security Volume: 24 Issue: 8 Dated: (August 1987) Pages: 38-41
Date Published
1987
Length
4 pages
Annotation
Circumstances monitored by the electronics office of Yosemite National Park include fire and intrusion, the counting of visitors entering certain areas of the park, and warning about excessive levels of air and water pollution.
Abstract
Passive infrared sensors at doorways protect fauna and flora displays at night. During the day, infrared sensors trip a relay to tally the number of visitors entering the Happy Isles Nature Center. Sensors monitor the operation of three sewage stations that pump water to a treatment plant outside the park. If a pump fails or the sewage level threatens to spill into the Merced River, detectors trip a digital dialer which alerts the dispatch center. Using underground cables that tabulate the number of cars entering the park, the system identifies congested areas. In a mile-long tunnel, equipment monitors hazardous air conditions. To protect visitors from hazardous areas, plans are underway to install fiber optic fence strands that sound a warning alarm when broken. The article describes improvements the electronics technican wants to make. Illustrative photographs.