Raspberry Pi SPL meter

• Sound Pressur Level meter with RPI implemented with Python.
• Author: Seyoung Park
• Date: 2016 Feb. 23rd

Demo

Requirements

HW

• Raspberry Pi(1 or 2)
• Microphone (Webcam)

Docker

I made a Docker image for non-gui version.

# Run this command at the project dir
# Pull the image
docker pull shinyeyes/rpi-spl-meter:v0.1

# Enter the container
docker run -it --privileged -v /dev/bus/usb:/dev/bus/usb shinyeyes/rpi-spl-meter:v0.1

# Run this command in the container
$HOME/miniconda/envs/spl-meter/bin/python spl_meter_text.py

GUI version

SW

• Python 2
• EasyProcess==0.2.2
• numpy==1.10.4
• PyAudio==0.2.9
• PyVirtualDisplay==0.1.5
• scipy==0.17.0
• selenium==2.52.0
• wheel==0.24.0

Filter: A-weighting

I applied A-weighting to filter to filter the stream. A-weighting results frequencies which average person can hear. For further information read: Frequency Weightings - A-Weighted, C-Weighted or Z-Weighted? For the actual programmatic implementation I borrowed the code from endolith and is saved as /spl_lib.py. A-weighting() is translated from [MATLAB script](: http://www.mathworks.com/matlabcentral/fileexchange/69).