Novel animal hair-based sensing and energy harvesting technique for precision livestock farming wearables

In this paper we present a triboelectric device for motion sensing or kinetic energy harvesting in precision livestock farming (PLF) wearables. Triboelectric kinetic energy harvesting has proven to be an attractive research topic in the past decade. Triboelectric effect occurs when two dielectric materials - the triboelectric pair - found on the opposite sides of the so-called triboelectric spectrum, are brought into contact. During contact, a charge separation occurs which causes a voltage potential between the electrodes deposited on the materials. In our research we found that animal hair is in fact a perfect triboelectric material with high positive charge affinity. If animal hair is brought into contact with a suitable negative affinity charge material like Polytetrafluoroethylene - a strong charge separation occurs. In our research we've discovered a way to establish charge separation at discrete points on the animal skin or inside the animal hair layer by using a specifically designed array of charge collecting electrodes. Two different manufacturing techniques are tested: a) 3D printing with animal compatible and b) laminating conductive fabrics. The resulting devices are then tested in the lab by employing robotic manipulators under different loading conditions and with different animal hair samples - cattle, sheep & reindeer. The devices presented in this paper could in the future result with low-cost alternatives to accelerometers or could be used to develop self-powered collars for PLF applications.