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On Thu, 30 Oct 2003 20:03:44 -0500,
Ed wrote:
better add a generator coil on the sending unit or you will be going up
the mast monthly to replace the batteries. unless you are suggesting
actually reading the spinning blades from the optical sensor on the
deck.... Then.... I would worry about no signal in the rain....

BUT... you still have halyards to bang around at the dock.... unless you
also invent a "skyhook".



Parallax wrote:
I read this article on the most recent Practical Sailor where they
discussed wires slapping inside the mast. Strangely, this has never
bothered me although I bet it does now (cancel my subscription before
they make me aware of more things to be bothered by). So....Useless
idea #3436

Wireless mastop anemometer

A simple anemometer cup that turns a bar code like reflective wheel on
top of the mast. This wheel would be very lightweight (ounces) and
about 6" in diameter. it could also be arranged to show wind
direction and wind speed. On deck, next to one of the shrouds is a
little penlight diode laser/receiver shining up toward it. The laser
is of course modulated with a sin wave so the reciever can use a
lock-in amp to see the signal in any noise and it reads the bar code
like reflector. Sails dont block it cuz its inside the shrouds.


Actually, the wireless anemometer idea isn't half bad. A couple of
reflector disks on the wheel, and a low power laserdiode on the mast, or
someplace that it can "See" the anemometer wheel without the sails or
other stuff blocking it. Put a sensor next to the LD, add a small uProcessor
like one of the neato little atmel units, and salt with some C to taste.
I've done similar things for remote tachometers, pretty much the same
thing. You'd have to do something more to get wind direction, but for
masthead wind speed, it would likely work. I don't see any real
stumbling blocks. You *might* be able to get away with a high powered
LED instead of a LD, save some power there, but not sure. Only question
I have is how much salt spray and general crud it would take to reduce
the albedo of the reflectors down to the point they no longer reflected
enough light. But I suspect it wouldn't be much of a problem really.

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--
Jim Richardson http://www.eskimo.com/~warlock
If you can tell the difference between good advice and bad advice,
you don't need advice.