(Last updated 4th September 2016)
I started working on this project in summer 2014 to see if it was possible to record bat calls in my garden using a Raspberry Pi, having been inspired by the electronic devices on Tony Messina’s website and also those on Frank Pliquett’s website. Following the success of my early attempts, I have been continuously updating and modifying the design to incorporate new features. Keep checking back to this site for further updates – I am working on other features such as sound activated recording and automatic uploading to the cloud (e.g. Dropbox), and will add more details when available.
So far, I have successfully recorded around six or seven different species. The recorded calls can be analysed and a spectrogram created, which can aid in the identification of the bat. There are some good books about species identification from bat calls – these are provided in the links page.
The project started with a simple way of recording bat calls using a Raspberry Pi and Audio Card with a single push-button to start and stop recordings. Details of this design can be found here. I still use this version for unattended recording.
The latest version (spring 2016) has the features shown below, each of which can be selected from a colour touch screen. An overview on how to make this version is here.
An updated version (autumn 2016) with a 5″ colour HDMI touchscreen can be seen below.
This type of recorder/detector is not meant to replace professional models which are available, but is a good starting point for those interested in bats and cannot justify spending £1500 on a bat recorder/detector with similar features! It is possible to make a very capable device for around one-tenth of the cost, or less.
- Real-time full spectrum recording (192kHz sample rate)
- Real-time peak frequency display
- Real-time spectrogram display (4 second update)
- Continuous time-expansion playback
- Time-expansion recording
Real Time full Spectrum Recording
Spectrograms from recordings made with a Raspberry Pi bat recorder can be found here.