Noisedetector

A configurable noise detector that can call a webhook or email you if a certain level of noise is detected. I have this setup to only run after 8pm and over a certain threshold it calls a webhook that then fires off some IFTTT actions, such as a push notificaiton on my phone.

ruby-noise-detection

Noise Detection Ruby Script

Installation

The noise dector ruby script uses two linux tool to record and analyse de output: sox and arecord. So you need to install these packages on your raspberrypi (or other linux system):

sudo apt-get install sox alsa-utils

Then, in the current version, the script does not accept parameters to change file location (log, tmp recording and pid file), so you need to allow the script execution user (pi for example) the write access to these files and folders:

RECORD_FILENAME='/tmp/noise.wav'
LOG_FILE='/var/log/noise_detector.log'
PID_FILE='/etc/noised/noised.pid'

or you can edit the script changin these variables values with what you prefer for your system.

Detect Audio Card

pi@raspberrypi ~ $ noise_detection.rb -d
Detecting your soundcard...
 0 [ALSA           ]: BRCM bcm2835 ALSbcm2835 ALSA - bcm2835 ALSA
                      bcm2835 ALSA
 1 [U0x46d0x8d7    ]: USB-Audio - USB Device 0x46d:0x8d7
                      USB Device 0x46d:0x8d7 at usb-bcm2708_usb-1.2, full speed

Test Audio Card Record

pi@raspberrypi ~ $ noise_detection.rb -t 1
Testing soundcard...
Samples read:             40000
Length (seconds):      5.000000
Scaled by:         2147483647.0
Maximum amplitude:     0.013245
Minimum amplitude:    -0.041565
Midline amplitude:    -0.014160
Mean    norm:          0.013523
Mean    amplitude:    -0.013466
RMS     amplitude:     0.014662
Maximum delta:         0.023560
Minimum delta:         0.000000
Mean    delta:         0.003664
RMS     delta:         0.004679
Rough   frequency:          406
Volume adjustment:       24.059

Starting Noise Detection with Alert

noise_detection.rb -m 1 -n 0.30 -e me@server.com -v

The script will be started in background

Terminating Noise Detection

noise_detection.rb -k

Setup your webhook

I used IFTTT which you can read more about on the url below. Primarly to get this up and running you will need to edit the trigger with your trigger name and also your unique key.

https://help.ifttt.com/hc/en-us/articles/115010230347-Webhooks-service-FAQ