“I wanted to build a TinyML model that could detect when a boat is nearby by listening for it on a hydrophone. Edge Impulse makes it easy to build ML Models that can run on an Arduino board and detect events in audio. The tricky part ended up being how to connect a hydrophone to an Arduino board. I looked around but didn’t see any existing boards for powering and amplifying a microphone, like the hydrophone… so I decided to build one!
I started by modifying the Electret Microphone module from Adafruit. It powers and amplifies the microphone. I just popped off the included microphone and wired in a 3.5mm jack so I could plug in the hydrophone. While this worked… it wasn’t very sturdy or compact. To fix this I decided to build my own Featherwing form factor board based on this design.
One of the the things I love about Adafruit is that they make there board designs available open source. I was able to take this design, move it over the the Feather form factor and add a 3.5mm jack instead of the microphone. I am not the best at this, but the board does work. If you have improvements to design, please make suggestions!! There is a small amount of noise, but the audio quality is more than good enough to perform ML based boat detection and has successfully worked in the field.”