[sdiy] Reading holes (voids) on piano paper rolls.. using Photo-transistors and PIC micro..

[Roman Sowa]

If the holes are so small as in the picture and it works with 
pneumatics, you have nothing to worry about using single optotransistor. 
If sensor is placed few mm behind the hole, light will be difused in all 
directions anyway, so it will have no problem picking light from all 
parts of the pickup hole. You may not even notice the dotted nature of 
long notes punched in paper roll when observing it on a scope.

Roman

W dniu 2022-11-11 o 18:21, Jean-Pierre Desrochers pisze:
>
> >>I'd use two LEDs next to each other, and two receivers next to each 
> other, and read both ....  00 is blocked 01 or 10 is passed.  11 
> shouldn't happen.
>
> I cannot do that because of the height of each square holes on the 
> brass reading bar..
> See this photo.. each square holes cannot accommodate 2 receivers.. 
> only one optic fiber each so one receiver each allowed.
>
> Thanks anyway for your comment !
>
>