(#588) Re: IrDA receiver

Message posted to the Speak Freely Forum
  by Duane M. Cook on Sat, 27 Dec 2003 04:50:41 +0100 (MET).
  http://www.fourmilab.ch/wb/speak-freely.pl?rev=588

  Reply To: (#584) IrDA receiver
  Author:   imran
  Date:     2003-12-26 20:35

: I am trying to make a IrDA infra red receiver
: powerfull enough to receive another
: infra-red receiver (transmitter) from the
: range of 1000-2000 meter radius (180d swip
: span). The transmitting device could be any
: handheld PDO even like Palm Zire a cheap
: PDOS.
: I wonder if any one know any wonderful idea in
: this field to improve/amend existing
: device???

I don't want to sound too negative, but your concept doesn't have a viable
solution. We experimented w/IR device communications when I worked at
UCBerkeley. Even if you had enough power in the IR device, IR is very sdubject
to defraction from numerous sources. The main problem is moisture in the air.
Remember the IR device obeys the inverse square law, any defraction reduces
the delivered signal to the remote receiver. Thermals and window glass
distortions do the same thing.

The preceeding assumes that you have installed an extensive lens system, at
both sides, to help focus the emitted and received signals.

In short, it relly is a fruitless effort, especially at that distance.

SRI,
Duane


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