Changing volume in Python program on Raspbery Pi

Question

I use Raspbery Pi B+ 2. I have a Python program that uses the ultrasonic sensor to measure the distance to an object. What I would like to is change the volume depending on the distance to a human. Having a Python code to obtain the distance, I have no idea, how can I change the Raspbery Pi volume by a code in Python.

Is there any way to do that?

Answer 1

You can use the package python-alsaaudio. The installation and usage is very simple.

To install run:

sudo apt-get install python-alsaaudio

In your Python script, import the module:

import alsaaudio

Now, you need to get the main mixer and get/set the volume:

m = alsaaudio.Mixer()
current_volume = m.getvolume() # Get the current Volume
m.setvolume(70) # Set the volume to 70%.

If the line m = alsaaudio.Mixer() throws an error, then try:

m = alsaaudio.Mixer('PCM')

this might happen because the Pi uses PCM rather than a Master channel.

You can see more information about your Pi's audio channels, volume (etc..), by running the command amixer.