Light-powered GPS collar removes tether to batteries

Catching bison is a hassle. It’s also expensive. For most, these truths are intuitive — just think about how big the net would have to be — but for a few, the knowledge comes firsthand. Researchers from the World Wide Fund for Nature (WWF) Ukraine, who have direct experience catching the creatures, recently worked with Saule Technologies to develop special bison-tracking collars powered by light.

The tracking technology uses perovskite solar cells that are inkjet-printed onto bendable substrates. In addition to accommodating a bison as it grows and moves, the flexible solar cells make an attractive accent to the all-white collars, and the cells resist damage from impact — helpful for when a rival bison becomes jealous over the fashionable accessory.

A European bison sports a solar-powered tracking collar. Courtesy of Bohdan Vykhor/WWF Ukraine.

Perovskite solar cells are perfect for the application of animal tracking, said Vivek Babu, project leader at Saule Technologies. “They work in all [lighting] conditions, including shadowed areas, and they can be integrated into a flexible collar.”

WWF aims to help increase the European bison population in Europe, particularly in Ukraine. Tracking the animals enables the organization to better understand the bison’s habitat and helps with managing general herd movement.

The project team chose to test the prototype on a bison population in the Lviv region of Ukraine, on grounds called the Styr Hunting Enterprise. During a recent visit to the site, the team captured and collared two bison, which they named Adam and Ewa. After initial testing with the pair, the team will work to further optimize the collar and its functions.

The prototype telemetry collar uses a GPS sensor that tracks the animals’ locations and sends data via the LoRaWAN (long-range wide-area network) communication protocol, which connects rechargeable battery-operated devices to the internet in regional, national, or global networks. The collars — as well as the tracking application and the transmission infrastructure — were designed, built, and installed by Saule Technologies, with guidance and support from WWF Ukraine.

Use of solar cells enables a much longer lifetime for the tracking collars and removes the need to replace batteries — something that bison rarely remember to do and with which they tend to resist help.