In accordance with an embodiment of the invention, a human interface device communicable with a computing device and method therefor for varying a process selectably performable by the computing device is disclosed. The human interface device comprises a positionally variable controller of the human interface device actuable and positionable by a user of the human interface device. The human interface device also has a communication interface for communicating with the computing device for varying intensity level of an intensity-variable property of the process selectably performable by the computing device in response to the actuation and position of the positionally variable controller. More specifically, the process is selectably performable by the computing device is selectable by at least one process selection key actuable by the user of the human interface device.