Patent ID: 6887162

Claim:
An apparatus for providing an output dependent on an orientation of a moving object relative to its direction of movement, comprising: (a) light-reflective means carried with the object for movement with the object in the direction of movement, the light-reflective means defining three reference locations on the object, the three reference locations being spaced from one another on the object in the direction of movement, and each of the three reference locations being displaced on the object from alignment with the other two of the three reference locations; (b) detection means for defining a narrow detection plane transverse to the direction of movement, the detection means being responsive to movement of the light-reflective means through the detection plane, the detection means comprising: (i) light-emitting means for emitting light transversely of the direction of movement for reflection within the detection plane from each of the three reference locations individually during movement of the object through the detection plane; and (ii) light-responsive means responsive to the light reflected within the detection plane from each of the three reference locations individually to provide an electric signal, the electric signal having a waveform that varies in amplitude with time in accordance with the movement of the object through the detection plane, the light-responsive means comprising means for generating the electric signal to have a waveform that includes amplitude excursions corresponding to the light reflected within the detection plane from the three reference locations respectively, each amplitude excursion being generated progressively in real time as the respective reference location passes progressively through the detection plane, and the amplitude excursions having relative timings within the waveform synchronised to passage of the respective reference locations through the detection plane; and (c) means responsive to the waveform of the electric signal for providing the output, the output being provided in accordance with the amplitude excursions and their relative timings in the waveform.