Hi,
these are too expemsive for me, i want to use it for robotic .
Yeah, but that's what they cost, these are not your average sensors.
look at the botom of the page herehttp://wiki.droids-corp.org/index.php/Microb_Technology/2009/Beacon
That's a home built unit, so you need to build it yourself if you want one.
Or, better yet, start using a Sharp distance sensor and get to know how that works first - only a few (well off) people use the factory made LASER sensors and I don't think you would get much out of it, that you cannot have with a much cheaper Sharp, at your present level of knowledge, so it would be a waste of money anyway.