I've been reading some more about ultrasonic tracking beacons, so I wanted to play a bit with those.. Hackaday even spoke about those http://hackaday.com/2017/05/04/ultrasonic-tracking-beacons/ !

The first step is to get a microcontroller, a micro, and we're set. The setup looks like this:

First, I've tried with a 32u4.. the limited RAM onboard was problematic. So I took something a bit more powerfull - a feather WICED - which I used to acquire bits of 160ms (see below) - ~ 8k points at 50kHz.

Now, let's try and see if we can isolate a clear 8kHz signal : indeed - documented on github !

The only thing that bugs me is that the FFT libs for the WICED are not yet well developped .. si I can't definitely use the WICED as a stand alone so far. Dang.