Hey all,
Im looking to try and make a small machine which counts the number of sheets of paper that slide out of a printer, and moves a servo every time 15 sheets of paper has been counted.
I am not too sure which is the best approach for this. Would an IR sensor work? And, if so, having never worked with one before, what tips would you have for me on this mini project of mine. 
Thank you in advance
The main problem will be the mechanical arrangement to ensure the sheets properly trigger the sensor.
If you can arrange the motion of the paper so that each sheet separately passes through an IR beam-break sensor then, yes, that would be a way of providing a signal to count the sheets. An IR sensor can easily be arranged to cause an Arduino I/O pin to change between HIGH and LOW.
Another idea that comes to mind is to allow the sheet to pass over a metal plate on which a very light metal spring is touching. The contact between the plate and the spring makes an electric circuit which gets broken when the paper slides between the spring and the plate.
...R
As @Robin2 states, if you can guarantee a gap between sheets something like this would work.
Hi,
If the sheet away from the printer, then you could have a IR or optical sensor detecting the outlet slot of the printer.
Each time the beam goes from broken (paper in the slot) to beam clear (no paper coming out of slot), you count 1 sheet.
Tom..
Do you count one sheet or two when you print on both sides of the sheet?
Paul
Paul_KD7HB:
Do you count one sheet or two when you print on both sides of the sheet?Paul
For the decades I was in the cut-sheet high-speed laser printing world, a "sheet" is a physical piece of paper regardless of whether it's printed on none, one or both sides, and the sides were usually referred to as "pages" or "images".
So a (then) high speed cut sheet laser printer from the early 80s as an example, would print at 120 pages (sides) a minute. That would result in 120 sheets (pieces of paper) delivered to the bin each minute for a pure simplex (single-sided) job, or 60 sheets a minute to the bin for pure duplex (double-sided).
(It used to piss customers off when they thought that pages were pieces of paper, and expected 120 sheets a minute duplex, which would have been 240 sides a minute.)