Pampering Penguins in the Pittsburgh ZooNovember 1, 2006 By: Dirk Kalp, Walter D. Tauche Sensors
Keeping three species of penguin contented in the zoo exhibit they now call home requires wireless monitoring and correction of the temperature and humidity inside their quarters.
The world's 17 species of penguin are indigenous only to the Southern Hemisphere, including the Antarctic. Gentoo, Macaroni, and King penguins are anything but native to Pittsburgh, PA, but nonetheless are very much in their element at the Pittsburgh Zoo and PPG Aquarium, thanks to a sophisticated system of sensors and a wireless network that keeps everything in balance.
The birds thrive at temperatures below 50°F, and it is important to maintain them at those low temperatures to avoid heat stress and decrease susceptibility to disease. Pittsburgh summers can bring 90°F weather, making the air chillers in the penguin habitat work overtime. Identifying performance issues and predicting failure for the air chiller system and associated power supplies—before the situation becomes critical—provides valuable corrective action time.
Rather than rely on visual observations, temperature and humidity are electronically monitored in various locations within the exhibit. Because intrusion into and disruption of the exhibit would compromise the structure and stress its feathered inhabitants, wireless temperature sensors provide the only realistic solution.
Reliable Monitoring amid Piping, Pumps, and Penguins
To create a natural environment for the penguins (Figure 1), the exhibit consists of masonry block and concrete walls, fiberglass-reinforced plastic scaffolding and walkways, metal railings, piping and pumps for water circulation, and metal and wire underlayment within the artificial rock and brick. These surroundings provide a fairly harsh environment for common, low-power radio frequency (RF) communication.
Figure 1. Three species of penguin enjoy the ambient conditions of their native habitats— thousands of miles from home
For ease of deployment, simplicity in configuration, and reliability in communication, the implementation team selected components from the Sensicast SensiNet wireless sensor network coupled with IntelliSensor's NiteWATCHMAN sensor data management software.
As in any real-world application of intelligent wireless system networks, cost and reliability are major concerns. The penguin habitat added a nonintrusion factor to these requirements. IntelliSensor performed an engineering evaluation of the site that determined that the placement of six wireless temperature and humidity sensors would provide reliable data acquisition and adequately measure the temperature profiles necessary (Figure 2).
Figure 2. Deployment pattern used for reliable temperature and humidity monitoring
Six Nodes Send Reliable Signals
Node 1. The first SensiNet Smart Sensor for temperature and humidity is located in a shaded area on the roof to measure the outside air temperature.
Node 2. The second temperature sensor is just inside and to the left of a steel door to the isolation area of the exhibit.
Node 3. The third temperature sensor is inside the isolation area of the exhibit behind a plastic grate which, when open, permits the penguins to enter the isolation area. This acts as a redundant temperature and humidity sensor.
Nodes 4, 5, and 6. Node 4 (Figure 3) is inside the exhibit, hidden from view behind a simulated rock ~3 ft. above the penguin floor and is the primary temperature sensor. Node 6 is inside the exhibit on a reinforced concrete walkway ~15 ft. above the penguin floor, where it measures temperatures ~10 ft. below the roof of the exhibit. Temperature sensor Node 5 is also above the penguin exhibit floor, ~6 ft. higher than Node 6 and at the opposite side of the exhibit.
Figure 3. SensiNet Node 4 is hidden behind a simulated rock 3 ft. above the exhibit floor
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