What is the range of distances you need to measure?please.....in need your help...here the refference that i got..
hi steve, emm..yap this project is quite to old, but i still want to know how about the kind of silicon photodiode i must used it and also the circuit that worked for this project, n then firstly, i don't get idea to combined with circuitThat's a confusing idea.. it doesn't seem too practical, although it claims simplicity and ease of manufacture.
I think you need to read the patent fully to understand the concept, then try to replicate the solution via obtainable parts. The lightsource and photodiode are the least of your worries, especially without understanding the overall concept.
From what I gather, you need a collimated source to be reflected from an object. The light returns, but somehow gets blocked by a shade. Apparently this shade is movable, which makes me think that there is a subsystem which keeps the light from striking the photodiode(s). The position of this shade can be used to determine, through triangulation, the distance from the reflecting target to the unit itself.
This patent is quite old, so I would tend to stay clear of this particular idea. I designed a 2D distance measurement system a couple of years ago that used a line laser and a 1M pixel CMOS image sensor. It only took a couple months to design and worked quite well. Another idea is to look into position sensitive detectors (PSDs) to do this. Another method is time-of-flight, which requires an extremely fast clock/counter or a very precise phase detector.
Steve
by Duane Benson
by Don Wilcher