Cacophonometer – robust, inexpensive ecology monitoring tool

Smart phone in water proof container with opening at bottom for sound recording

This project initially started with the goal of creating a tool to dramatically improve monitoring how the environment responds to predator eradication. In New Zealand we are lucky that the bird song is literally the canary in the mine:

  • Lots of bird song = relatively healthy eco-system
  • No bird song = probably a rat infested dead zone 

It is estimated over a thousand audio recorders have been used in New Zealand but there is no central place where these recordings are stored. They are also often over short, inconsistent time periods. 

Our theory is that if we make high quality sound recordings over consistent time periods and store them in a central database that is time, date and GPS stamped, it will allow for better analysis of trends than current speculations, which are mostly subjective.Data could answer questions such as: 

  • Are bird numbers going up or down? 
  • What types? 
  • How fast are we losing/gaining birds?

This device will create an objective measure of the Cacophony (noise) of bird song – hence why it is called a Cacophonometer. We use a modified cell phone to run an app and gather this data. The app allows you to set up sound sampling and sends the data to the cloud. To the right is a photo of our working prototype.

The sound files are uploaded to the server and there is a webpage that allows you to listen to any of the files. 

At the moment we do not have tools for analysing the sound but there are lots of clever folks working on this. However well we can analyse the data today is almost irrelevant given Moore’s law and the fact that we get better at it every year. Our goal is to collect and store the recordings in the best quality format possible.

Improvements for the future include:

  • Create a quick, simple set of instructions to allow anyone with an old cell phone and wifi to start collecting bird song data in their area of New Zealand.
  • Develop a filter to automatically delete any human voices (we  want to eliminate the possibility of privacy issues). Ideally all data would pass through this filter before being uploaded.
  • Full testing of the solar charging system.
  • Finding a better external microphone to plug into phone.
  • Remote calibration with Tone from phone speaker.
  • Make the app available for consumers so when they go for a bush walk it can collect sound samples and sync when they return home (turning  many people around the country into an environmental monitor).
  • Build a business making and selling Cacophonometers( a great opportunity for anyone keen – let us know as we already have a list of folks who would like to buy one).