Provided is a method for controlling an ultrasonic motor to reduce noise sounding during low-speed rotation in a surveying instrument adopting the ultrasonic motor for a rotary shaft, and a surveying instrument for the same. In a method for controlling an ultrasonic motor according to an aspect of the present invention, in a low-speed rotation range of an ultrasonic motor, a ratio of an acceleration period as a time of application of the drive signal in a control cycle is controlled, and a time to start the acceleration period is randomly shifted for each control cycle. In a method for controlling an ultrasonic motor according to another aspect, a time to start the acceleration period is regularly shifted for each control cycle. In a method for controlling an ultrasonic motor according to still another aspect, second-half acceleration control and first-half acceleration control are alternately repeated.

An example apparatus is described which comprises a rotary member supported by a bearing. A rotary encoder is registered with respect to the rotary member to rotate therewith and a sensing arrangement is registered with respect to a surface of the bearing. The sensing arrangement is responsive to rotation of the encoder to generate a signal indicative of a rotational characteristic of the rotary member.

An optical encoder for which improved robustness is sought comprises: a movable part bearing a scattering zone and an absorbing zone, a light emitter that is positioned to emit light radiation in the direction of the movable part, a sensor that is sensitive to the light emitted by the emitter, the sensor being positioned to detect light radiation that is reflected by the scattering zone, the movement of the movable part making it possible to place either the scattering zone or the absorbing zone on an optical path between the emitter and the sensor, and an optical waveguide that is transparent to the light radiation and that is passed through by the optical path.

Embodiments of the present disclosure provide an optical encoder for an electronic device. The optical encoder comprises an elongated shaft and a plurality of markings axially disposed around a circumference of the elongated shaft. The optical encoder also includes an optical sensor. In embodiments, the optical sensor includes an emitter and an array of photodiodes. The emitter and the array of photodiodes may be radially aligned with respect to the elongated shaft or axially aligned with respect to the shaft.

Rotary encoders suitable for inclusion within small form factor devices (e.g., as input devices to small form factor electronic devices) are disclosed. In one aspect, a light source can illuminate a pattern on a rotatable shaft in order to reflect the pattern onto an array of optical sensors. Each optical sensor from the array of optical sensors can be polled at the same time to yield a snapshot vector. The snapshot vector can be projected onto a subspace spanned by two vectors selected in part on the pattern of the rotatable shaft and the distance separating the shaft and array. The resulting projection can be used to determine error and phase of the reflected pattern across the array of optical sensors. The phase of the reflected pattern can correlate to rotation of the shaft.

An apparatus for sensing a rotating body includes a rotating body including a detection target portion; a pattern portion disposed in the detection target portion in a direction in which the rotating body rotates; a frame that rotatably supports the rotating body; a first sensor disposed to oppose a first region of the detection target portion; a second sensor spaced apart from the first sensor and disposed to oppose a second region of the detection target portion; and a holder portion coupled to the frame to hold the first sensor and the second sensor.

The instant disclosure provides a scanning light-guiding encoder by forward focusing including a light-guiding grating wheel, a light-emitting module and an optical sensing module. The light-emitting module is surrounded by the light-guiding grating wheel. The optical sensing module includes a plurality of sensor elements adjacent to the light-guiding grating wheel, and a plurality of exposed sensor areas of the plurality of sensor elements are offset in the transverse direction and are arranged along a plurality of different horizontal lines parallel to each other.

An encoder system includes a signal processing circuit including: (1) a first position data detection circuit that detects first position data representing positional displacement in rotation of an input shaft through first predetermined signal processing based on a first detection signal input from a first absolute position encoder; (2) a second position data detection circuit that detects second position data representing positional displacement in rotation of an output shaft through second predetermined signal processing based on a second detection signal input from a second absolute position encoder; (3) a position data combination circuit that combines the first and second position data to generate combined position data representing the number of rotations of the input shaft and the positional displacement within one rotation of the input shaft; and (4) a position data comparing and collating circuit that compares and collates the first and second position data.

In one embodiment, a satellite microphone assembly for use in teleconferencing or other audio based communications comprises a base housing a microphone and volume control electronics. The base is enclosed by a cylinder, rotatable about the base and having a top surface configured to be an actuatable button to toggle a mute/unmute status of the microphone. The cylinder has a sidewall configured to be engaged by a user such that the user can rotate the cylinder. An optical sensor is supported by the base, and is configured to detect a rotation of the cylinder and to output information about a direction and a degree of rotation of the cylinder to the volume control electronics, causing a rotation of the cylinder to affect the volume level of a speaker.

A rotation detecting device includes a rotation operation part configured to be rotationally operated, a first detector configured to detect a rotation of the rotation operation part and output a first rotation detection signal, a second detector configured to output a second rotation detection signal, with a predetermined phase difference with respect to the first rotation detection signal, a third detector configured to output a third rotation detection signal, with each of a predetermined phase difference with respect to the first rotation detection signal of the first detector and a phase difference with respect to the second rotation detection signal of the second detector, and a controller configured to, based on the first rotation detection signal, the second rotation detection signal, and the third rotation detection signal, perform detection of a failure of the first detector, the second detector, or the third detector.