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From: kellym@ether.UUCP (Kelly M McArthur)
Newsgroups: sci.electronics
Subject: Weather monitoring on my PC
Keywords: weather
Message-ID: <1522@ether.UUCP>
Date: 5 Jan 91 22:54:40 GMT
Reply-To: kellym@ether.UUCP (Kelly M McArthur)
Organization: HALF, Beaverton, OR
Lines: 52
Distributiion:

I'm interested in building a gizmo that will allow me to monitor
local weather conditions on my PC.  Specifically, I would like 
to stick a data aquistion contraption on my roof, and have it 
send information about current temperature, wind speed, wind
direction and barometric pressure to my computer.*  The PC end 
of things, software and parallel/serial ports, is clearly
pretty generic.  But I'm interested in any clever ideas people
might have for building the outdoor sensors.

My ideas so far include:

Temperature- the easy one.  Reverse bias transistor junction, amps,
A/D.  Something like that.  I'll have to look it up...

Wind Speed- Say, if we need an A/D, and some kind of communications
like twisted-pair serial, let's throw a 68HC11 in this thing.  Then 
we can bag the DC-motor-attached-to-a-model-airplane-propellor 
annemometer, and go with a fan that interrupts the beam of an LED/
phototransistor pair, and have software do the rest.  Hmmm...

Wind Direction- Let's see.  If I'm only concerned with approximate
wind direction, N, NNW, NW, WNW, W, etc. that means I only need to
resolve things into 16 possibilities.  Cool.  How about a simple 
Gray code wheel and four LED/Phototransistor pairs for a simple 
shaft position encoder?  

Barometric Pressure- Uhhh. Well, I guess I need one of them 
Pressure Transducer things.  Kind words of advice in this area would
be greatly appreciated.

Time- another cool function might be to listen in on WWV to set the 
time on my computer with reasonable (but not fanatic) accuracy.  
I think this has been discussed before.  Anyone have the details on
how to do this?


If you have any suggestions, send me mail and I will summarize your 
collective brilliance in a followup posting.


* Yes, I imagine that such things are commercially available, 
  but I'm interested in trying to hack one together myself for
  the fun of it.  (a foolhardy notion I'm sure I'll live to regret)

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"We [Americans] don't know what we want, but we're ready to 
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*	Kelly McArthur		..tektronix!sequent!ether!kellym   *
*	HALF Associates		(Heavily Armed Lunatic Fringe)     *
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