This project contains a small script to control the AC power of an audio power amplifier using an Kasa smart plug when connected to CamillaDSP on a RasperyPi. The "RPi4 + CamillaDSP Tutorial" setup is descirbed in this thread of the Audio Science Review website.
The script can use any of the plugs from that the python-kasa can control. In my case I used the HS103 device.
The script looks for the status of the playback device on the linux process information pseudo-file system:
$ head /proc/asound/card2/stream0
MOTU M4 at usb-0000:01:00.0-1.3, high speed : USB Audio
Playback:
Status: Stop
Interface 1
...
and checks the stream for a Stop or Running status and uses that to turn the smart plug on or off.
To use, first make sure you install the python-kasa library as per the instruction and can control the device from the command line. A good article on who to do this is here.
Then clone the library, modify as required and:
cd camiladsp
git clone git@github.com:igfarm/amp_power.git
cd amp_power
Test the script
python3 amp_power.py
After you are satisfied it works, install it as a service. To do this update amp_power.service to point to the correct path and then:
sudo cp amp_power.service /lib/systemd/system/
sudo systemctl enable amp_power.service
sudo systemctl daemon-reload
sudo systemctl start amp_power.service