The optoNCDT 1710-1000 sensor has a measuring range that starts from a distance of 1 meter from the sensor, so displacement can be measured at a distance of 2 meters from the sensor.
The OPB733TR reflective object sensor measures 0.300 inch by 0.160 inch with a PC board-mounted profile of 0.114 inch and incorporates a lensed IR LED and phototransistor elements.