Patent ID: 8357043

Claim:
A motion determination apparatus comprising: a fixed main unit; and a movable operating device, held by an operator, that detects body motions of the operator and for transmitting signals to, and receiving from, the main unit, the operating device comprising: an acceleration sensor that detects acceleration; a light emitter that emits light; and a transmitter that transmits a value detected by the acceleration sensor to the main unit, and the main unit comprising: light receivers arranged at least at two positions, each receiving light emitted from the light emitter and detecting an intensity of the received light; a position detector that performs a process of detecting a position of the operating device based on the intensity of the received light detected by each of the light receivers; a storage device that stores history of each position of the operating device detected by the position detector; and a motion determiner that determines whether the operator has performed a predetermined motion on the basis of the history of the positions of the operating device and the detected value of the acceleration sensor, wherein the motion determiner determines whether an extension and retraction motion of the operator has been performed based on the relationship between a first determination distance of a first position detected by the position detector and a second determination distance of a second position previously detected immediately before the detection of the first position by the position detector, the first and the second determination distances being a distance between an origin and a position detected by the position detector after the origin was detected, with the origin being a point of a position detected by the position detector immediately before acceleration of equal to or greater than a predetermined standard value is detected by the acceleration sensor.