Quick summary
Ocean noise can negatively impact marine life in a variety of ways, including causing injury, increasing stress, and interfering with communication, navigation, or foraging. As a result, the acoustic environment should be considered in the care of a marine animal in captivity. This is challenging due to the high costs of monitoring systems and the complexity of acoustic data analyses. We have developed the NOise MOnitor (NOMO), a low-cost, open-source, smart acoustic recorder that can monitor noise levels in an aquarium environment, conduct on-board processing to derive simple noise metrics, and automatically share the results online at regular intervals.
The system is very similar to our drifting recorders. It is based on an inexpensive electronics package (Raspberry Pi with analog-to-digital converter expansion board) enclosed within a waterproof case, combined with one or two hydrophones. The use of a Raspberry Pi, which is a fully functional Linux computer, allows for wireless communication and onboard data processing. Our team has successfully used a similar electronics package housed within a drifting buoy to collect noise measurements at sea. The total cost per NOMO is about $1000 USD, and all software and hardware will be published online such that can be available for use and further development by other aquariums and research groups.
All the latest code and build instructions are available on the project github repository