Techniques for interpreting orientation invariant motion are disclosed. Unlike a prior art controller (e.g., a WII game controller) that has a specific physical design to induce or force a user to grip the controller in a consistent way, a disclosed controller does not have such a physical design and allow a user to grip the controller in any way that is comfortable to the user (e.g., around an axis z), one or more transformation or rotations are designed to transform or rotate readings from inertial sensors housed in the controller to readings independent from how the controller is being gripped by a user.