There is a crossing sensor at point A for a bicycle. When the bicycle passes point A(the sensor senses the object and then does not), a light turns on for 20 seconds. If the bicycle goes in reverse now and passes through point A again nothing must happen.(Again the sensor only senses something and then it doesn't once the car passes.)
The difficult part of this is that the sensor changes from true to false very quickly because the bicycle moves away. If the bicycle stayed on the sensor; it would be easier. Another difficulty is the way back because it also doesn't stay.
Any propositions? I would appreciate any help. Note My skills in labview are quite mediocre. Though I would like to learn more.
Using two sensors at Point A, one in front of the other, would give you the bicycle direction which would allow you to determine when the bicycle is in reverse. This assumes that the sensors have a read response fast enough to distinguish between the front and back sensor.