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

Equipment

• Digital sound meter - (Tonda SL-814)
• Raspberry pi
• Camera module
• Python script to record sound levels and image or video clips
• Apache
• d3.js

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:
http://sigrok.org/wiki/Tondaj_SL-814

Initialize

serialport.write('\x10\x04\x0d')

Poll

serialport.write('\x30\x00\x0d')

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: https://www.citysoundmap.com/example.html (data collected in Moab, UT August 2013).

Github: https://github.com/lukevanhorn/citysoundmap