Newsgroups: comp.robotics
Path: brunix!sgiblab!spool.mu.edu!olivea!decwrl!decwrl!netcomsv!netcom.com!nagle
From: nagle@netcom.com (John Nagle)
Subject: Re: laser diode safety
Message-ID: <nagleCCEoF2.KzD@netcom.com>
Organization: NETCOM On-line Communication Services (408 241-9760 guest)
References: <1993Aug26.084151.2444@hemlock.cray.com> <1993Aug26.151805.28818@newshub.ariel.yorku.ca>
Date: Fri, 27 Aug 1993 06:52:14 GMT
Lines: 20

cs911225@ariel.yorku.ca (KEN E WILLMOTT) writes:
>>From: browen@lyapunov.aoc.nrao.edu (Bruce Rowen)
>>I found a Laser diode once and pondered using it as a transmitter that
>>would be so powerful, you could flash it in a room and the reflections
>>could be received *anywhere*. (did you ever look at a IR led with a
>>CCD camera with no IR filter? Damn bright!). Well (as R. Reagen would
>>say), I dug the diode out from my junk collection a while back (these
>>can be bought for about $5) and set up a power FET driver that would
>>send 10 amp pulses through the thing at a 1% duty cycle. The receiver
>>was a fat photo diode and low noise op amp circuit to test for the
>>signal.

       Where did you get these things?  I've never seen a laser diode
that could handle 10 AMPS.  Around 30mA is typical for a 5mW laser diode.
Laser diodes are available up to about 30mW (interestingly, they don't
draw much more current than the 5mW diodes; they're more efficient, with
better mirrors.)  And they cost from $20 to around $150.
I'd love to get a few of these giant 10A laser diodes for anything like $5.

					John Nagle
