Abstract: The musical tone control apparatus generates a musical tone control signal in response to a motion at a certain part of a human body, preferably a bending motion at an articulation of a finger, wherein it includes a light emitting element, a photo-conductive member and a light receiving element. The light emitted from the light emitting element is transmitted through the photo-conductive member whose light transmission rate varies in response to the force applied thereon, so that the amount of the light transmitted through the photoconductive member is reduced. Such reduced amount of the transmitted light is received by the light receiving element. Based on the received light, the musical tone control signal is generated. Thus, by bending the photo-conductive member, the musical tone control signal can be varied. Preferably, the light emitting element is a photodiode, the photo-conductive member is an optical fiber, and the light receiving element is a phototransistor.

Abstract: This invention discloses an optical circulator compatible with optical glass fiber transmission lines in optical communications in the wave length range of 1.0.about.1.7 microns. An optical circulator embodiment of the invention utilizes a magneto-optic circulator cylinder with the entry and reflective ends, at least three coupling glass-fiber transmission lines being connected to the entry end. The biasing magnetic field is applied in parallel with the common axis. This circulator embodiment of the invention possesses advantages in consisting of minimal constituents, and in being easy to make and simple to adjust.

Abstract: An automatic guiding device for an indoor goods transporter comprising a path detector being responsive to stationary guiding facilities and controlling a steering means of the vehicle.