Weather
Station Papers and Remote Sensing Experiment
(Updated May 2014)
When I lived in Los Angeles, I was interested in
building an anemometer, but can’t remember why.
The wind was always pretty gentle, but maybe we had some storms that
made me want to know the speed. I was
familiar with electronics, and read about some Hall-effect sensors. These are non-contact integrated circuits
that use the proximity of a simple permanent magnet to trigger a pulse. They seemed perfect for an anemometer sensor,
since they would not add friction. I got
some Leggs pantyhose egg containers and a small ball
bearing, and put together this prototype.
I calibrated it by attaching it to my car and driving down a road on a
windless day. The display had a live
analog readout as well as a peak-reading digital display, all made with a few
logic circuits. Computers were not yet
used for this kind of thing in the early 1980s!
I sent an article describing the anemometer to “Popular
Electronics” magazine, but they passed it along to a new hobby magazine called “Hands-on
Electronics”. The anemometer appeared in
the second issue, Fall 1984. The magazine lasted a few more years.
When I moved to Colorado, I lived on the side of a
mountain where the gusts were really high, sometimes over 70 mph. I built several copies of my anemometer, but
used spun aluminum hemispheres and an aluminum enclosure. I attached one anemometer to my chimney in
1989, and rarely saw a day where the minimum speed was less than 10 mph. Based on the histogram of the data recorded
over nearly a five year period shown here, the mean highest daily speed was 29
mph. This might be a little exaggerated,
since the sensor was about 30 feet higher than the surrounding terrain, and on
the down-slope of the front range of mountains.
It was interesting, enough, however, to try to find
an even windier place. I could see snow
blowing on Pikes Peak, and thought that it would be fun to set up an anemometer
there. I could not see the summit from
my home, only a little peak a few miles south, on a place called “Windy Point”,
near the Pikes Peak Cog Railway route.
The distance from this point to my home was 10 miles, so I needed
an optical link. I arranged permits with
Pike National Forest and the City of Colorado Springs, who shared ownership of
the property. The altitude was about
12,600’, but accessible from the summit or a water department service
road. I went up once to survey the spot,
once to set it up, and one year later to remove it when the permit
expired. I had some family and friends
help in the setup. I tested the LED
transmitter (five super-bright red LEDs with collimating lenses) with a 10”
Fresnel lens receiver over a 10 mile range in the city, and had plenty of link
margin. The setup had a rechargeable
battery with a solar panel, and sent back data for a few minutes every night
about an hour after sunset. The data was
the live pulses from the anemometer, so I could only measure the live wind
speed. I used an oscilloscope at the
receiver to monitor the pulse rate.
After aligning the transmitter, gluing the guy wires to some rocks, and
adding more rocks for stability, the experiment was a success! This was one of the most fun projects I’ve
worked on.
After a few months, the data stopped
transmitting. I was able to see the red
LEDs with binoculars from other parts of the city, and they failed to appear one
evening. When I went to retrieve the
hardware, it was apparent that small animals had chewed through the connecting
wires. It was not clear if that was the
root cause, or the transmitter got misaligned, or the battery failed to
charge. I could tell that the anemometer
was still standing, by photographing it through my 6” telescope.
I submitted a lengthy article to the Amateur
Scientist column in “Scientific American”, and it was accepted for
publication. Unfortunately, the magazine
column’s new editor (Forrest Mims III), was replaced after a very short tenure,
apparently over his religious views.
They apparently could not find a replacement editor with a strong
experimental background. They cancelled the
Amateur Scientist column for the next five years, so my article was never
published.
Tesla
Coil Paper and High Voltage Projects
Laser
Experiences at Hughes Aircraft and Kaman Sciences
Stellar
Products Adaptive Optics