An image of two dogs and a bison wearing harnesses with the energy harvesting system. Text next to the animals says Dog 1 (Exp. 1), Dog 2 (Exp. 2), Dog 2 (Exp. 3), and Wisent (Exp. 4)

Kinefox Tracks Wildlife For A Lifetime

Radio trackers have become an important part of studying the movements of wildlife, but keeping one running for the life of an animal has been challenging. Researchers have now developed a way to let wildlife recharge trackers via their movements.

With trackers limited to less than 5% of an animal’s total mass to prevent limitations to the their movement, it can be especially difficult to fit trackers with an appropriately-sized battery pack to last a lifetime. Some trackers have been fitted with solar cells, but besides issues with robustness, many animals are nocturnal or live in dimly-lit spaces making this solution less than ideal. Previous experiments with kinetically-charged trackers were quite bulky.

The Kinefox wildlife tracking system uses an 18 g, Kinetron MSG32 kinetic energy harvesting mechanism to power the GPS and accelerometer. Similar to the mechanical systems found in automatic winding watches, this energy harvester uses a pendulum glued to a ferromagnetic ring which generates power as it moves around a copper coil. Power is stored in a Li-ion capacitor rated for 20,000 charge/discharge cycles to ensure better longevity than would be afforded by a Li-ion battery. Data is transmitted via Sigfox to a cloud-based database for easy access.

If you want to build one to track your own pets, the files and BOM are available on GitHub. We’ve featured other animal trackers before for cats and dogs which are probably also applicable to bison.

Comparing Solar Energy Harvesters

There doesn’t have to be much more to setting up a simple solar panel installation than connecting the panel to a battery. Of course we would at least recommend the use of a battery management system or charge controller to avoid damaging the battery, although in a pinch it’s not always strictly necessary. But these simple systems leave a lot on the table, and most people with any sizable amount of solar panels tend to use a maximum power point tracking (MPPT) system to increase the yield of the panels. For a really tiny installation like [Salvatore] has, you’ll want to take a look at a similar system known as a solar energy harvester.

[Salvatore] is planning to use an energy harvester at his small weather station, which is currently powered by an LDO regulator and a small solar cell. While this is fairly energy efficient, the energy harvesters that he is testing with this build will go far beyond what an LDO is capable of. The circuit actually has two energy harvesters built onto it which allows him to test the capabilities of both before he makes a decision for his weather station. Every amount of energy is critical when using the cell he has on hand, which easily fits in the palm of one’s hand.

The testing of this module isn’t complete yet, but he does have two working prototypes to test in future videos to see which one truly performs the best. For a project of this size, this is a great way to get around the problem of supplying a small amount of power to something remote. For a larger solar panel installation, you’ll definitely want to build an MPPT system though.

Continue reading “Comparing Solar Energy Harvesters”