If you spend much time in a woods, you start to realize that the sounds that travel the furthest are ones that sound like drums. Is it a coincidence that Native Americans frequently used drums? No — they were definitely used for long-distance communication.

Elephants, whales, and other animals use infrasound to communicate over very long distances. Low-frequency sounds travel further than high-frequency ones.

emergency backpacking drum

So the question arises — is it possible to create a collapsible drum that can be used by a backpacker for emergency communication? The typical emergency signalling devices are whistles (high frequency, so it won't travel as far) and mirrors, but a drum could be a useful addition.

I'm stopping work on this, and I haven't implemented or even refined the idea much. But the current design is: