> From: "Mark A. Corio" <Mcorio@aol.com>
>
> In a message dated 96-10-21 23:47:55 EDT, you write:
>
> >If you insist on a purist approach, try using a high intensity LED e.g.
> >3 cd or more.  Failing that, a 1mW red laser diode should give heaps of
> >signal
> >if you spread it just a little bit with a lens to avoid alignment problems.
> >Since it is monochromatic, you could also use a corresponding red filter
> >on the receiver end to make it more immune to ambient variations.
> >
> >Note that laser diodes require the correct constant current driver otherwise
> >the (expensive) magic smoke can escape very easily.
>
> You should also be aware that laser light is considered dangerous and is
> controlled by government oversight.  You must stay within appropriate
> regulations and even then you may be able to be sued by the idiot trying to
> see what the inside of a laser looks like (now known as one-eye).

Hardly! 1mW is below the level considered hazardous.  In any case, the
beam will be expanded by a lens so the radiation gathered by the pupil
will be a lot less than 1mW.  If you stick the appropriate laser class
sticker on it, then you are covered.  If I can get a 3mW laser pointer
with a label merely saying 'Caution: laser radiation / do not stare
into beam' then the poor bloke should be able to run his demo in a
controlled environment.

General gripe: it's a cryin' shame that the world is becoming dominated
by lawyers and doctors and other nay-sayers.  Australia seems to be
shouldering some of that litigious weight that the US is buckling
under, where morons are able to turn plain bad luck (with a healthy
dose of their own stupidity) into mountains of gold (all at taxpayers'
expense).  I mean some of the payouts are just ridiculous!  Rant rant
rave rave...

Regards,
SJH
Canberra, Australia