Abstract: A shaft angle encoder adapted for use in a hand-held gyroscope has a motor at the core of the gyroscope suspended by two pairs of orthogonal gimbals to provide two-degrees-of-freedom for the inner gimbal. Power is provided to the motor through conductive elements in the bearings without limting the range of motion of the gyroscope. An electro-optical shaft angle encoder for detecting the rotation of the inner gimbal with respect to the outer gimbal includes an optical pattern mounted along a cylindrical portion of the inner gimbal about the axis of rotation of the inner gimbal and in alignment with one of the outer gimbal bearings. A light source and a rotational phase plate are mounted to the outer gimbal and aligned with this optical pattern and a light path is provided through the optical pattern, the rotational phase plate, and the outer gimbal bearing.