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I am looking for a solution that detects sound and sets GPIO21 to low and GPIO21 to high, after 5 minutes when there is no sound. I need it for a streamer (Raspberry Pi) that will run shairport-sync, tidal-connect and spotify. When sound is detected, GPIO should trigger my amplifier. Unfortunately I can not code python, so I hope someone can help

JanLP
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2 Answers2

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I think you might find this link helpful: Detecting audio. You shouldn't need all of the code in that answer, just the part on detecting silence.

I believe you can use the python gpiozero library for using the GPIO ports. You should be able to treat it as an LED.

import gpiozero     #For GPIO
import time         #To sleep


###REPLACE THIS WITH YOUR OWN FUNCTION (Like the one I posted in the above link)###
def is_silent():
    return True

pin = gpiozero.LED(21)  #Set up the GPIO pin

pin.on()        #Turn it on

seconds_since_sound = 300   #Set seconds since last sound to high

while(True):
    if(is_silent):      #Check if there is no sounds
        if(seconds_since_sound >= 300):         #If there is no sounds and it has been more than 5 mins since the last sound
            pin.on()        #Turn on
        else:
            seconds_since_sound += 1        #Otherwise increment by a second
            time.sleep(1)   #Sleep for a second
    else:
        seconds_since_sound = 0         #If there is a sound then set timer to 0
        pin.off()       #Turn off

Unfortunately I am unable to test if the code works as I do not have access to a raspberry pi.

It looks like the silence detection does not work in python 3.

EDIT:

It looks like you can record the soundcard on some devices using this line of code:

import pyaudio    #import pyaudio
p = pyaudio.PyAudio()   #setup pyaudio
stream = p.open(format=FORMAT, channels=CHANNELS, rate=RATE, input=True, output=True, frames_per_buffer=CHUNK_SIZE, input_device_index=2)    #open pyaudio stream

snd_data = array('h', stream.read(CHUNK_SIZE))    #Capture data (should be done in while loop)

return (max(snd_data) > threshold)    #Check if data is louder than threshold

(Change the input device index to point to the output of your sound card)

Once again, I am unable to test if this works as it only runs of python 2. It uses pyaudio.

SolveItPlanet
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  • Thanks for your reply. Unfortunately, it does not work. There is no error and the GPIO part is correct. It just detects no sound, unfortunately. – JanLP Nov 21 '21 at 02:06
  • Does your raspberry pi definitely come with a microphone and what version of python are your running? – SolveItPlanet Nov 21 '21 at 12:08
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@SolveltPlanet It is disabled via #dtparam=audio=on and I have Python 2.7.16 installed. Here is aplay -l

**** List of PLAYBACK Hardware Devices ****
card 1: AUDIO [SMSL USB AUDIO], device 0: USB Audio [USB Audio]
  Subdevices: 0/1
  Subdevice #0: subdevice #0
JanLP
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