Cacophonometer Update – Try it out

I once heard that when you think an IT project is 99% done, you are probably half way there.  A lot of work has been done on the Cacophonometer over the last few months and it is now ready for you to try it out.


The Cacophonometer is an app that runs on Android phones that makes regular sound recordings.  It can be used to gather ‘base-line’ and ongoing data of the bird song near the device.

Recent modifications

  • Privacy: The recordings uploaded to the server ( ) can now only be listened to by the person who makes them and can also be deleted if you have inadvertently recorded a private conversation.
  • Off grid:  The previous version worked well with mains power and wifi.  We have now successfully tested the current version while operating from a 5 watt solar panel and sending the recordings to the server using the regular cellular phone network. 

What you need to do

If you would like to participate (and to be honest that means testing) then here is a list of things that you will need to consider and implement:

  • Phone – The app works on Android phones with an operating system greater than 2.3.3.
  • Download the app (see link at end of this article) and install it on the phone.  The easiest way to install it is to email it to an account that you can access from the phone.
  • Power – If you have mains power available then this is probably your easiest and cheapest option.  Otherwise I can recommend using the solar panel that we used (see link below).  However, phones with an operating system of 4.2 will need to be 'rooted' to enable enabling/disabling of airplane/flight mode.
  • If you are using a solar panel, then to save power you will also need to remove/disable as many apps/accounts/syncing/GPS/Bluetooth as you can.   Also, set the screen timeout and brightness to their lowest levels.
  • Data connection – If you can access wifi then this will be the cheapest option.  I had success with a wifi extender plugged in at a shed between my wifi router and the phone location.  Otherwise you can install a SIM and use phone data (approximately 60 MB per month).  If you already have a phone that works on the Spark network, then they have offered us free data – get in touch so we can send you a SIM to try.
  • Weather protection -  You will need to protect your phone from the rain while still allowing it to hear the birds.  If you don’t have a convenient shelter, then I can recommend the DIY solution of a 1 litre ice cream container with some holes in the bottom – see pictures below.  The holes will need to be sealed up (hot glue gun works well) to stop the onslaught of wild animals - slugs in my case

If you want to have a go, I’d be very keen to hear how you get on.

Future work

  • Deploying to a local gully to undertake harsher testing.
  • See the ‘Removing voices from birdsong’ blog post to see how we are working on reducing privacy issues.
  • Moving to a new server – you will need to change setting in app when this happens.

Stuff to buy for your setup

Solar panel - approximate cost: US$26

Usb cable if you don't have one - approximate cost: US$1.5

Microphone - approximate cost: US$1.60  Or you could try the microphone that might have come with the phone's ear phones but I'm currently having mixed results with the one I found.

DIY enclosure setup

I'll let you be the judge of my DIY skills!  Suggestions for improvement most welcome.

Here you can see the overall setup.  Solar panel tied to the tree (currently in some shade) and the ice-cream container on the tree trunk. 

Inside container showing that it is screwed to the trunk and holes in bottom for solar panel cable connection and sound. I was worried about rain getting in and so made as few holes as possible. Recordings might be improved with more holes.

Place a sheet of plastic (from another ice cream box) at back of box to guide any water that enters down to

Place phone in box and connect cable.

To stop phone moving I packed the box with two pieces of scrap polystyrene (yeh – found a use for that packing that came with the last thing I shouldn’t have bought).

Lid on and ready to record. We’ve had a lot of rain recently but none seems to have entered the box.

With microphone attached - much better results than using the phones built in mic.

We have also trialed a more professional enclosure that we can use when deploying in large numbers.


The following figure shows a battery charge / discharge cycle when using the solar panel.



Tim Hunt 26/04/2017, updated 19/06/2017