Penguins Beat Heat at Zoo, Thanks to Pitt

A wireless technology touted for its potential to power cell phones and hearing aids currently is helping to ensure that penguins at the Pittsburgh Zoo and PPG Aquarium live in frosty comfort.

Radio-frequency (RF) battery charger technology developed in Pitt’s School of Engineering powers a wireless sensor that monitors the temperature in and around the penguins’ habitat. Although it’s being used experimentally at the zoo, the charger technology is so convenient and effective that it should have numerous scientific and commercial uses in the future, say those who work with it.

The charger came into play after the penguin habitat’s air-cooling system began allowing temperatures to rise above the 40-degree ceiling for comfortable penguin living, said Allan Marshall, the zoo’s aquatic life curator. Temperatures in the habitat sometimes shot up to 50 degrees.

“Fifty degrees is not dangerous for the birds, but it’s definitely at the top end of the range,” Marshall said. “Penguins are built to keep warm. They don’t have mechanisms like sweating to release heat. They can very easily get overheated and become heat-stressed,” which makes them more vulnerable to disease.

IntelliSensor—a local company that specializes in wireless sensor networks—placed 15 wireless sensors in and around the habitat to monitor air temperature at various stages of cooling.

The sensors measure the temperature every few minutes and send the readings back to a computer, which is monitored by Marshall and other caretakers. If the cooling system malfunctions, Marshall and his colleagues can catch the problem quickly.

“That gives us an extra window to make repairs before temperatures start going through the roof,” Marshall said. “It doesn’t take long for that building to warm up.”

Wireless technology was key in monitoring the penguins’ habitat, both for the birds and their keepers, said Walt Tauche, IntelliSensor’s industrial applications manager. Wires and the work of installing them would have disturbed the animals and their home, he said. So, IntelliSensor powered the sensors with batteries—which, like most batteries, periodically need to be changed manually. Doing so requires tromping through the penguin habitat or wiggling into air ducts every four to eight months when the batteries die. IntelliSensor opted to test the RF-powered battery charger on one of the sensors.

Patented by Pitt in 2001, the basic RF technology is licensed to Powercast, a company based in Ligonier, Pa. On its Web site, Powercast boasts that the technology can use radio waves to wirelessly and continuously charge cell phones and other devices. Tech Web sites have buzzed about the technology in recent months.

The RF charger stems from a simple and old idea, said Marlin H. Mickle, the Nickolas A. DeCecco Professor of Electrical and Computer Engineering and Telecommunications in Pitt’s engineering school. Mickle led the group that developed the charger.

Mickle came up with the idea of using early radios, known as crystal sets, as a model for converting RF into power, a technique called RF power harvesting. Crystal sets worked without any wires—the sets snatched the waves out of the air and used that energy to produce sound through an earphone.

“We thought, ‘If you’ve got enough energy to drive an earphone, what else can you drive?’” Mickle said.

He and his group used an electric device to constantly generate radio waves. Those waves feed into a receiver on a microchip board and are then converted to electric power by a diode, which allows for energy flow in only one direction. Thus, a device with an RF power source is always receiving a charge, without the need for wires.

“It’s not going to replace oil,” Mickle said, with a laugh, “but it replaces wires. You’re able to power something remotely, and it doesn’t require hands-on maintenance. They’re easy to apply once you get them to work.”

Beyond penguins and cell phones, possible uses include powering devices on radioactive sites or in hard-to-reach areas like the nests of cliff-dwelling birds, said John Voytko, president of IntelliSensor.

“There are certain cases where we absolutely cannot get to batteries to replace them periodically,” he said. “I think this technology is going to be very important. Power is always an issue.”

At the zoo, Tauche of IntelliSensor has replaced some batteries twice since installing the temperature sensors in the penguin habitat almost a year ago—but not those recharged through RF, which he expects will last three or four years. “During that time we will have gone through 10 or 15 [traditional] battery packs at least,” he said.

As Marshall reads a temperature report, he looks over the portion where the computer notes when sensor batteries need replacing. He comes to the line for the RF-charged battery.

“This one just says ‘Never,’” Marshall pointed out, chuckling. “They can pretty much run forever.”