Using parameters in your node

Next, we’re going to implement parameters into the fake sonar driver. Parameters are stored at ROS Master and can be accessed through node handles. Please see Parameters tutorial for reference.

1. Use the default value version of the param() function to gain the following features to the fake sonar driver:
   • if the parameter frequency exists on the parameter server, use its value in the sine function.
   • if the parameter is not specified, fallback to a default value.