Abstract: A self-orienting motion sensor in which an inner housing, preferably spherical, is free to rotate within a cavity, also preferably spherical, resting on a support in an outer housing. The inner housing has a preferred orientation due to the center of gravity being lower than the rotational center of the inner housing. Motion sensing elements are arranged within the inner housing to measure at least one and preferably three directions of motion. A signal transfer mechanism transfers signals to a recorder. The inner housing may include a magnet to orient it in a defined relation to the earth's magnetic field and the housing may be provided with ground engaging devices to fix the housing in the ground.

Abstract: A self-orienting motion sensor in which an inner housing, preferably spherical, is free to rotate within a cavity, also preferably spherical, resting on a support in an outer housing. The inner housing has a preferred orientation due to the center of gravity being lower than the rotational center of the inner housing. Motion sensing elements are arranged within the inner housing to measure at least one and preferably three directions of motion. A signal transfer mechanism transfers signals to a recorder. The motion of the inner housing may be limited in a pre-determined range, the inner housing may include a magnet to orient it in a defined relation to the earth's magnetic field and the housing may be provided with ground engaging devices to fix the housing in the ground.