> The way to collimate is to put the two binoc halves facing each other,
> level, and aligned, say two metres apart. Set focus on both sides to
infinity.
> Look into the one, and put a powered led at the eye position on the other
> one, and move/focus until brightest. fix in place.

It's almost certainly not critical here, but do note that IR and visible
light will focus at slightly different positions due to wavelength
differences. Brain says IR will be slightly further away but do check that
I'm right. Once you have the basic system working then observing signal
while moving receiver along axis will probably be fine.

I still think that an IR TX LED and a 38 KHz receiver sound like an ideal
way to go and should be able to achieve the range with ease with optics -
not that I've tried it myself of course :-)



        Russell McMahon

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listserv@mitvma.mit.edu with SET PICList DIGEST in the body