[Laser] "How to" page for laser pointer communications now online

[C. Turner]

Hello,

Although my main interest has been the use of high-power LEDs for 
optical through-the-air communications over long distances, our 
testing/experimentation has also included the use of lasers - including 
cheap <$3 laser pointers.  Even though we still think that LEDs are 
better for such things, given the ubiquity of laser pointers and their 
relative ease-of-use, there is no reason to ignore them.

Because we already have built highly-sensitive optical receivers - and 
in our LED experiments we have already set them up (that is, pointed 
them) it is fairly easy to throw into the mix some experiments with 
laser pointers - and having already-aimed receivers makes things simpler.

Having done these sorts of experiments/tests for several years means 
that we have done our share of hitting our heads against the wall and 
(hopefully) learning what works - and what doesn't.  This has allowed us 
to develop various techniques and build a few simple pieces of equipment 
that help in the setting up of such links.  We now have it so that we 
"routinely" set up 2-way laser pointer to laser pointer contacts over a 
20+km distance without much difficulty and have, on several occasions, 
set up 1 and 2-way laser-pointer communications over a distance of 
greater than 172km (107 miles) - which, we *think* is the current 
distance record for terrestrial 2-way voice-on-laser communications.

The URL of this page is:  
http://modulatedlight.org/optical_comms/using_laser_pointers.html

As with other pages at the site, this one is often being updated, so 
things will be added/changed from time-to-time, so feel free to send a 
comment (using the link at the bottom of the page) for 
suggestions/changes.  Of course, there are other ways to do things 
besides what has described - and if you are successful in doing so - let 
us know!

73,

Clint
KA7OEI