From: John Tserkezis 
Reply-To: Fidonet AVtech Echo 

Bob Lawrence wrote:

>  Jeeze! You're the sysop. If you don't know, what hope is there for
> the rest of us?

  Remember that last netmail I sent you regarding that non-fido zone?  That was 
the last time I looked at my BBS.  And not since as well.

> JT> I remember there being a contenst some time back on how far you
> JT> can use IR transmission on one led. The trick is to keep the
> JT> temperature down. Some have gone as far as liquid cooling
> JT> (nitrogen comes to mind but I can't remember if they were this
> JT> fanatical) the die directly. That is, hacking the bottom of the
> JT> led off to access the die instead of just cooling the leads. 
> 
>  ROFL! Bloody hell. Bloody idiots.

  Hey, anything to win the prize.  (I think it was a single chip micro dev. kit 
or something).

>  LEDs are really clever. The die is sealed with a lens of its own, on
> the chip, and the package is another lens.

  I've seen raw leds on a board, used for backlighting LCD displays.  The leds 
in those things are exposed, that is, you could see and touch the wire that 
goes to the top of the led.

>  That's the catch... battery power. They're quite greedy if you run
> them continuously, even pulsed on a short duty cycle.

>  What surpised me when I went right into it, was that an ordinary
> remote is so close to the ultimate range anyway. When I was testing
> Chinese TV, I used to complain if it went under 5 metres with fresh
> batteries, but if you try to get over 20m, you're really struggling.  

  Easy to take for granted, till you actually try to do it yourself.

> JT> Dunno what environment (or range) Brenton needs.

>  Outdoors... 20m. 

  Can it be focussed?  Or is it a hand-held device that needs to be portable?

-- 
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Linux Registered User # 302622                         http://counter.li.org>
Fido: 3:712/610  BBS/FAX: +61-2-9716-8310  Internet: jt{at}techniciansyndrome.org

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