Abstract: An instrument for determining angular inclinations includes a rectangular frame having a generally transparent rotatable disk positioned therein. The disk includes a weight that is gravitationally attracted to the Earth's surface and circuitry for determining the disk's relative rotational position. A light source and sensor surround the disk and cooperate to determine the disk's angular position according to opaque lines imprinted on the disk's surface. The instrument includes a speech generator having a memory in which a plurality of audible messages corresponding to respective angular inclinations are stored. The instrument includes logic circuitry for determining an appropriate message to be generated according to the sensed position of the disk. This message is emitted through a speaker. The instrument further includes visual indicators relative to the angular inclination of the frame.

Abstract: An instrument for determining angular inclinations includes a rectangular frame having a generally transparent rotatable disk positioned therein. The disk includes a weight that is gravitationally attracted to the Earth's surface and circuitry for determining the disk's relative rotational position. A light source and sensor surround the disk and cooperate to determine the disk's angular position according to opaque lines imprinted on the disk's surface. The instrument includes a speech generator having a memory in which a plurality of audible messages corresponding to respective angular inclinations are stored. The instrument includes logic circuitry for determining an appropriate message to be generated according to the sensed position of the disk. This message is emitted through a speaker. The instrument further includes visual indicators relative to the angular inclination of the frame.