according with first picture :
a: Rain Collector
b: Magnetic load
c: Sensor Mounting
d: Out put magnetic pick-up sensor
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Picture 1 is position 1
Picture 2 is position 2
Picture 3 is position 3
Picture 4 is Sensing Mode
Picture 5 V-out off magnetic pick-up sensor
Picture 6 Sensing diagram
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magnetic pick-up sensor work like lamp switch at home, using binary logical value: 0 and 1, 0 as off logic and 1 is on logic
when magnet pass trough sensor, sensor will be reacting changing logical value from zero to one,
or we can say
====:>>>
Pict 1 out sensor = 0 (off)
Pict 2 out sensor = 1 (on)
Pict 3 out sensor = 0 (off)
picture 4 to detail,
from that argument out logical value will count in ram or memory register using interrupt port and summarize value and multiply by 0,2 mm
using timer interrupt signal,
Sorry about my English if you don't understand about my topic just ask or quote