Hi all, I'm having trouble finding something online which isn't a very complicated device, but I don't know if it has a specific name, which would help me in a google search. I have a motor in an MBE which moves the sample, and I need a camera which can read to a computer what the distance is from the lens to whatever it sees, which is the arm attached to this motor. So I guess it might need a laser since it only needs to see the spot directly in front of the camera. The needed distance is only about 5ft or under. Is there a name for these devices? I've tried several search terms and have found nothing. It only needs to be accurate to about 5mm or so. Thanks.