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equation of the line. Using this as the point of origin, the distance, a, can be found to the
point (x,y), which corresponds to the current location of the sensor.
(x,y) a -
XX
Y
d
SStair Riser
Figure B-3: Stair riser model
The equation for this distance is shown in Equation B-1. Through the similar
triangles concept, the angle, 0, is shown on the two locations of Figure B-3. The angle, y,
is the user-defined angle of the infrared sensor. Using y and 0, the angle, T, may now be
found by:
=r-P (B-5)
The distance, f, is defined as:
f = a cos
Finally, the distance, d, may be found by:
d =
COS Z
(B-6)
(B-7)