Vitesze:
It's for measuring how close a waste bin (I share with other people) is to being full, so it can be emptied in time. I looked at several ultrasonic distance sensors already, but they don't appear to always be that accurate, so I would also like to see if there's alternative methods for this with the use infrared/laser sensors. The bin is roughly 2 meters high.
I think a good alternative would be a set of LEDs and light sensors at the FULL ENOUGH level of the waste bin. The Arduino can light the LEDs in sequence and check that all of the sensors detect the light. If any path is blocked it means there is some object at or above the FULL ENOUGH line.
A laser distance sensor will only work on one point. Three LEDs and three sensors can check nine lines across the opening.