Efficient sound activated recording

[dvaosta]

Hi,
for my thesis I need to use raspberry pi to capture sounds and analize them. To improve efficiency, I'm looking for an efficient way (a busy cicle is not an option) to start recording only when there is a noise loud enough.
So what I ask you is if it's possible to get an interrupt from the microphone or from an additional input device when a noise is detected.

[OutoftheBOTS]

yes there r lots of very cheap sound detectors. they simply just emit a high signal when a sound above a certain volume is detected, how load the sound neededs to be is adjustable by just screwing the pot in or out see https://www.aliexpress.com/item/Free-Sh ... 8.9.IcmRSh

[dvaosta]

Thanks.
So I connect the detector to a port, then I suppose I can use GPIO to associate an interrupt to it, right?

[OutoftheBOTS]

ok I haven;t played with 1 of these myself but have seen others use them successful to do what you want to do.

This is my understanding of them. Hook Vcc to 5v, GND to GND and out to your pin that you want to detect the sound on.

I believe that when a sound is dectected the sensor will pull the out pin to ground

for my code I choose pin 4 for the input pin for the sound.

Code: Select all

import RPi.GPIO as GPIO

INPUT_WIRE = 4

GPIO.setmode(GPIO.BCM)
GPIO.setup(INPUT_WIRE, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)

while True: 
  if GPIO.input(INPUT_WIRE) == GPIO.LOW : print" Sound detected"

the code can be shortened to this

Code: Select all

import RPi.GPIO as GPIO

INPUT_WIRE = 4

GPIO.setmode(GPIO.BCM)
GPIO.setup(INPUT_WIRE, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)

while True: 
  if not GPIO.input(INPUT_WIRE) : print" Sound detected"