Magnetic annunciator

Abstract

An annunciator for an organ stimulating system implantable in the body of a person comprises a hollow canister having a cylindrical internal cavity, first and second electrically conductive coils encircling the canister lying in transverse, preferably perpendicular, planes which intersect along the longitudinal axis of the internal cavity, and a cylindrical permanent magnetic roller having an outer peripheral surface engageable with an inner peripheral surface of the canister and being freely rotatable within the canister. The roller is magnetized at right angles to the roller axis producing a permanent magnetic field and signal generators, either AC or DC, sequentially energize the electrically conductive coils to produce a rotating magnetic field interacting with the permanent magnetic field of the roller and causing the roller to roll about the inner peripheral surface of the canister. The permanent magnetic roller, by its movement, produces vibrations which are imparted to the casing of the organ stimulating system. Specifically, the rolling motion of the roller results in a movement of its center of gravity in a vibration producing orbit. The orbital frequency, &OHgr;, of the center of gravity of the roller is b &ohgr;·d/(D−d), where &ohgr;=rate of rotation of said roller, d=diameter of said roller, and D=inner diameter of the cavity of said canister. In another embodiment, the roller may be replaced by a ball and the internal cavity may be spherical or ellipsoidal.