RE: IrDA
Check out:
http://www.alphalink.com.au/~derekw/upntcvr.htm
http://www.opticalpaths.com/
-----Original Message-----
From: Andrew Hakman [mailto:hakmanaļ¼ hotmail.com]
Sent: Sunday, August 19, 2001 10:52 PM
To: dev(a)seattlewireless.net
Subject: Re: IrDA
After just last month working on an optics project at the International
Summer Science Institute that dealt heavily with optics, I would have to
agree that radio waves are much easier to work with, and more forgiving
if
something isn't exactly precisely right. I, personally, would stick to
radio
for that reason (and a lack of time to get something to the precision
level
required for optics).
Andrew
> Everybody keeps talking about custom optical bridges and such,
but
> what about powerboosted IrDA links? Some guys at a MacHack a few
years
> back did something clever with lenses, diodes and a PowerBook
(or
was
> it iMac?) to extend an IrDA link over a fair distance (50 yards
or
> something). Could we not find some good optics and do the same thing
Yes, IrDA *can* be made to work over longer distances. In fact,
several
of the Ir network links that have been hacked together are using
IrDA. The protocol has a fair amount of overhead that really detracts
from the raw speed.
> over a much greater range? Not only would we be able to boost the
> power as much as we want (no FCC, right?), it would also be
difficult
> to eavesdrop in two ways: #1 you have to find the beam, and #2
you
> have to grab a piece of it without burning yourself.
Well..*someone* is going to complain if you hook up a 2MW laser:)
> Most newish
> (1999 on or so) laptops and desktops have full speed (4Mbps) IrDA
> built in, making amps and optics shouldn't be terribly difficult.
Bother of these things are probably more difficult then building a
decent
yagi antenna. I also suspect that the PowerBook's weren't
communicating
at 4mbps either.
> Patching a laser in instead of the regular diode shouldn't be
terribly
> difficult either.
I also suspect that that's be harder then you think. The trick is to
get
it fast. The commercial products don't use powerful lasers, they
use
damn
good optics and signal processing.
--Justin
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