A ROS package for tracking and changing audio volume level via a ROS node /volume which interfaces with amixer from alsa-utils.
To install, clone this repo into your catkin workspace, and then from the root of this workspace, enter the command catkin build volume. Then to run the volume node, source your workspace by running source devel/setup.bash in the workspace root, and lastly, enter the command rosrun volume volume.
The audio control to use with amixer defaults to 'Master' and can be set with the rosparam /volume/control, and the sound card number defaults to 0 and can be set with the rosparam /volume/card.
The latched topic /volume/percent contains the current percentage audio volume.
The topic /volume/percentSet can be published to, setting the volume level at the given percentage, e.g. 0 to mute audio, or 50 to the audio volume to 50%.
The topic /volume/percentChange can be published to, changing the volume level by the given percentage, e.g. -100 to mute audio, or 50 to increase the audio volume by 50% (up to a maximum of 100% of course).