City Sound Map

Sound Data Logger using the Raspberry Pi, digital sound sensor and Camera Module


This project uses a modified Tonda SL-814 digital sound meter weighted for pressure level A. The modifcations allow the meter to be powered from raspberry pi and remain in an always on state for continual polling.

I purchased this model

Though, I recommend this one as it comes with the special cable(non-standard USB), otherwise you'll have to modify a micro-usb cable.

The serial protocol has been reverse engineered and is available here:





The sound meter is polled continually, but only records data above the set threshold 70 dB(A)

If using the Camera Module, a photo or short video is also captured.

The Raspberry Pi can also host a simple web interface to view the data. Install apache or webserver of choice.

**note: The Pi user will need write permissions for the data, video and img directories in /var/www

Demo: (data collected in Moab, UT August 2013).