We have a pcb that sits close to some hole. When something passes through ( at 2-5cm distance) we have to detect it.
To me it seems that this area is still in the 90's . When I check my options, all of them are large modules of infra red devices, or ultrasonic modules.
These works great, but I was looking for something that can sit on the pcb, small, and simply detect light/sound/etc.
Something elegant , the size of a chip.
Are there things like that ?