You can configure LightShow Pi to use the input from a USB audio dongle as the audio your lights respond to (i.e. instead of playing local audio files). There are many applications that this can be used for, one of which is for adding a light show to an existing karaoke setup:
USB Audio Input Setup
Next, you’ll want set your USB audio sound card as the default soundcard following the instructions here.
LightShow Pi configuration
To enable audio-in mode, set the lightshow mode to audio-in in your configuration override file (e.g. ~/.lights.cfg):
[lightshow] mode = audio-in
There are other advanced options related to audio-in mode, take a look at the default configuration file for more details (search for “audio-in”).
Running in Audio-In mode
Once you’ve enabled audio-in mode, you can run the synchronized lights script to start things up: