Robert Werner lives in Alaska, where bears are quite common. While beautiful creatures, they can obviously be quite dangerous, and as an alternative to more “active” approaches for bear defense involving spray or firearms, Werner came up with a simple “Bear Troller,” which instead plays the sound of a snapping twig.
The idea here is that the sound of a twig snapping will cause a bear to immediately stop and pay attention to the noise source, as it’s something that both a predator and prey would make. Others try bear bells for this purpose with debatable effect, though to be fair, it doesn’t seem like this one has been tested in a bear encounter scenario.
The Bear Troller hangs on a lanyard inside of a 3D-printed enclosure. Power is provided by a 600 mAh battery, with a TP4056 charging board, and a solar panel to provide power when needed for a long hike. As seen below, the device is triggered by a button with a bear-shaped top, which triggers a DFPlayer MP3 module. This board conveniently includes an SD card slot and amplifier to emit the needed sound over a speaker.
This concept could, of course, be used for a variety of different purposes, though if you do plan on encountering a bear, it’s probably a good idea to have a backup plan as well!