10_SoundSensor_logging

Capturing and graphing sound level data

This .ino file can be used to produce output that can be captured on a macbook written to an rrd database and produce graphs

Seting up the database

We need to crate an rrd database where the sound data will be stored.

rrdtool create sound.rrd \
--step 10 \
DS:partysound:GAUGE:60:0:200 \
RRA:MAX:0.5:1:28800

Reading the usb port

To read the usb port serial output I have used a hack to read it using the logging function of the screen command. There could be a more canonical way to read from the usb port but this was what I was able to scrounge up for getting this to work for the party.

screen -L /dev/cu.usbmodem14101 9600

Please make sure you addapt the device to match your device. This will start writting what the adafruit device is outputing in a file called screenlog.0.

Capture the data and putting it in the database

We can now read what is written to the screenlog.0 file and write it to the database. We can do this in a terminal window and run it continously with the followitn command.

while true ; do  rrdtool update sound.rrd N:`cat screenlog.0|tail -1|egrep -o "[0-9.]*"` ; sleep 1; done

Generating the graph

We can now use the respective rrd command to create a graph of the captured data

rrdtool graph temp_graph.png \
-w 1000 -h 400 -a PNG \
--slope-mode \
--start -19200 --end now \
--vertical-label "sound pressure from CPX" \
DEF:sound1=sound.rrd:partysound:MAX \
LINE1:sound1#ff0000:""