Now that you explain that, i can see how it works.
How did i miss this(???):
“So if you wire the switch between input and ground, so the switch pulls the input to 0 V when it’s closed, you need a “pull-up” resistor to pull the input up to 3.3 V or 5 V when the switch is open. And vice versa”
I really need to read carefully this Directly connecting to Optical Pulse Counter with RPi? - #7 by pb66
Robert, i am very grateful for you help!
Thank you!
Celso