Wind chill

H

Howard Eisenhauer

Guest
Anybody know of a circuit to measure wind chill? I'm guessing the
best/simplest/cheapest way would be to measure how much current it
takes to keep a resister at certain temperature while exposed to Ma
Nature's little tantrums but I really don't feel like getting into a
theoritical design/prototype/troubleshoot/revise/build/yadda yadda
yadda project on this. Something I could get built & calibrated
before next summer would be nice- by next week would be fantastic :).

Thanks,

Howard.
 
"Howard Eisenhauer" <howarde@REMOVECAPShfx.eastlink.ca> wrote in message
news:ck1mv0lunogttc722jh1cm3c3bvargs6ce@4ax.com...
Anybody know of a circuit to measure wind chill? I'm guessing the
best/simplest/cheapest way would be to measure how much current it
takes to keep a resister at certain temperature while exposed to Ma
Nature's little tantrums but I really don't feel like getting into a
theoritical design/prototype/troubleshoot/revise/build/yadda yadda
yadda project on this. Something I could get built & calibrated
before next summer would be nice- by next week would be fantastic :).
Click to expand...
A temperature sensor and anemometer connected to a suitable MCU should do
what you want. You could use a lookup table based on this:

http://www.nws.noaa.gov/om/windchill/index.shtml

Leon
 
Howard Eisenhauer wrote:

Anybody know of a circuit to measure wind chill? I'm guessing the
best/simplest/cheapest way would be to measure how much current it
takes to keep a resister at certain temperature while exposed to Ma
Nature's little tantrums but I really don't feel like getting into a
theoritical design/prototype/troubleshoot/revise/build/yadda yadda
yadda project on this. Something I could get built & calibrated
before next summer would be nice- by next week would be fantastic :).
Click to expand...
IMO, machines don not feel windchill. It appears to be
connected to evaporating moisture from a surface.
As close a machine could come would be measuring
temperature, wind and moisture content of the air.

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net
 
On Sat, 29 Jan 2005 13:24:58 +0100, Rene Tschaggelar wrote:

Howard Eisenhauer wrote:

Anybody know of a circuit to measure wind chill? I'm guessing the
best/simplest/cheapest way would be to measure how much current it
takes to keep a resister at certain temperature while exposed to Ma
Nature's little tantrums but I really don't feel like getting into a
theoritical design/prototype/troubleshoot/revise/build/yadda yadda
yadda project on this. Something I could get built & calibrated
before next summer would be nice- by next week would be fantastic :).

IMO, machines don not feel windchill. It appears to be
connected to evaporating moisture from a surface.
As close a machine could come would be measuring
temperature, wind and moisture content of the air.

Rene
Click to expand...
Wind chill is very close to being a bogus idea. To the extent that it is
meaningful, it is meant to assess how much faster a person will cool down
in a moving stream of air than in a still stream of air of the same
temperature. So it is mostly about heat transfer under convection
conditions.

I think you are right that what the OP should do is focus on measuring
air speed and temperature, and possibly humidity. The wind chill could
then be looked up or calculated or whatever. I don't know exactly how they
calculate it.

--Mac
 
Fred Bloggs wrote:
If you don't know anything about it, then why are you posting an
opinion
about what the OP should do?
Click to expand...
Because this is Usenet.
 
larwe@larwe.com wrote:
Fred Bloggs wrote:

If you don't know anything about it, then why are you posting an

opinion

about what the OP should do?


Because this is Usenet.
Click to expand...
HAAHAH
 
Howard Eisenhauer wrote:

Anybody know of a circuit to measure wind chill? I'm guessing the
best/simplest/cheapest way would be to measure how much current it
takes to keep a resister at certain temperature while exposed to Ma
Nature's little tantrums but I really don't feel like getting into a
theoritical design/prototype/troubleshoot/revise/build/yadda yadda
yadda project on this. Something I could get built & calibrated
before next summer would be nice- by next week would be fantastic
:).
Click to expand...
Twc=33 + (T-33)(.474+.454sqrt(S)-0.0445 S) {siple (1945) }
T=ambient temp Celsius
S=Windspeed m/s
Holler if you need a version of this rendered down to 8051 assembler (needs
a 16 bit math package)
M
 
Mac wrote:

Wind chill is very close to being a bogus idea. To the extent that it is
meaningful, it is meant to assess how much faster a person will cool down
in a moving stream of air than in a still stream of air of the same
temperature.
Click to expand...
And it has to be a naked person. It was developed by the military
to act as a baseline for cold-weather gear. Anyone wearing clothes
will find that a 10 degree wind chill is much warmer than a real
10 degrees.

So why is it so popular? It makes the weather report on your local
TV station more exciting. A REAL correction factor that tells you
how cold it will seem while you are wearing a good coat would be
far more useful, but instead they give the bogus numbers.

Trivia: Inb the military tests, females complained about the cold
sooner but could tolerate a colder environment without having it
disable them.

(This spot reserved for Rich Grise so he can insert a joke about
frigid naked females...) :eek:
 
On Sun, 30 Jan 2005 14:54:36 +0000, Guy Macon
<_see.web.page_@_www.guymacon.com_> wroth:

So why is it so popular? It makes the weather report on your local
TV station more exciting.
Click to expand...
That's been my take on wind chill from the beginning.

Jim
 
Jim Thompson wrote:
On Sun, 30 Jan 2005 06:54:43 GMT, Mac <foo@bar.net> wrote:


On Sun, 30 Jan 2005 01:24:15 +0000, Fred Bloggs wrote:



Mac wrote:

On Sat, 29 Jan 2005 13:24:58 +0100, Rene Tschaggelar wrote:



Howard Eisenhauer wrote:



Anybody know of a circuit to measure wind chill? I'm guessing the
best/simplest/cheapest way would be to measure how much current it
takes to keep a resister at certain temperature while exposed to Ma
Nature's little tantrums but I really don't feel like getting into a
theoritical design/prototype/troubleshoot/revise/build/yadda yadda
yadda project on this. Something I could get built & calibrated
before next summer would be nice- by next week would be fantastic :).

IMO, machines don not feel windchill. It appears to be
connected to evaporating moisture from a surface.
As close a machine could come would be measuring
temperature, wind and moisture content of the air.

Rene


Wind chill is very close to being a bogus idea. To the extent that it is
meaningful, it is meant to assess how much faster a person will cool down
in a moving stream of air than in a still stream of air of the same
temperature. So it is mostly about heat transfer under convection
conditions.

I think you are right that what the OP should do is focus on measuring
air speed and temperature, and possibly humidity. The wind chill could
then be looked up or calculated or whatever. I don't know exactly how they
calculate it.

--Mac


If you don't know anything about it, then why are you posting an opinion
about what the OP should do?

There is a difference between "not knowing anything about" wind chill
(your words) and not knowing "exactly how to calculate it," my words.

You sure are a surly one. ;-)

--Mac


You misspelled "Shirley" ;-)

...Jim Thompson
Click to expand...
In your case a much more literal measurement of WCT is required: paste a
temperature indicating strip to your forehead and stand outside for an hour.
 
On Sun, 30 Jan 2005 17:15:30 GMT, James Meyer <jmeyer@nowhere.net>
wrote:

On Sun, 30 Jan 2005 14:54:36 +0000, Guy Macon
_see.web.page_@_www.guymacon.com_> wroth:


So why is it so popular? It makes the weather report on your local
TV station more exciting.


That's been my take on wind chill from the beginning.

Jim

Eh? Never been in Detroit this time of year have you ?:)
Click to expand...

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
On Sun, 30 Jan 2005 17:15:30 GMT, the renowned James Meyer
<jmeyer@nowhere.net> wrote:

On Sun, 30 Jan 2005 14:54:36 +0000, Guy Macon
_see.web.page_@_www.guymacon.com_> wroth:


So why is it so popular? It makes the weather report on your local
TV station more exciting.


That's been my take on wind chill from the beginning.

Jim
Click to expand...
The US and Canada switched to a new formula for calculating wind chill
in the fall of 2001. The difference between dry bulb temperature and
wind chill temperature is not as great with the new formula.



Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
On Sun, 30 Jan 2005 11:48:50 -0700, the renowned Jim Thompson
<thegreatone@example.com> wrote:

On Sun, 30 Jan 2005 17:15:30 GMT, James Meyer <jmeyer@nowhere.net
wrote:

On Sun, 30 Jan 2005 14:54:36 +0000, Guy Macon
_see.web.page_@_www.guymacon.com_> wroth:


So why is it so popular? It makes the weather report on your local
TV station more exciting.


That's been my take on wind chill from the beginning.

Jim

Eh? Never been in Detroit this time of year have you ?:)

...Jim Thompson
Click to expand...
I took the dog for a walk at night a week or two ago- the wind was
~20-30mph and temperature -22°C (-8°F). Taking a glove off to use my
Maglite and bag the leavings, I wasn't across an open field diagonally
before all the feeling was out of my little finger in that hand. Wind
chill is real enough!

A few miles in that sort of environment without proper clothing and
you could be dead. It's not nearly as bad without the wind.

A comfortable -1°C (30°F) and sunny today.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
Gareth wrote:

It seems reasonable, to me, that measuring the heat loss from a heated
resistor could enable you to calculate windchill in the way the OP
suggested.
Click to expand...
I'd suggest a sensor at body temperature, and measuring the power neede
to keep it warm.


Thomas
 
In article <10vpta5rgnmaj24@corp.supernews.com>, Guy Macon wrote:
Mac wrote:

Wind chill is very close to being a bogus idea. To the extent that it is
meaningful, it is meant to assess how much faster a person will cool down
in a moving stream of air than in a still stream of air of the same
temperature.

And it has to be a naked person. It was developed by the military
to act as a baseline for cold-weather gear. Anyone wearing clothes
will find that a 10 degree wind chill is much warmer than a real
10 degrees.

So why is it so popular? It makes the weather report on your local
TV station more exciting. A REAL correction factor that tells you
how cold it will seem while you are wearing a good coat would be
far more useful, but instead they give the bogus numbers.
Click to expand...
They did that a few years ago.

Before a few years ago, the windchill reported on the news was the one
for bare skin. And it took something like -30 degrees F on that scale to
achieve a windchill advisory. A really bad windchill that did not happen
most winters (in Philadelphia) was -40 degrees F and a day with both
strong wind and temperature slightly below zero managed around -50.

In recent years, they have been using a different windchill scale based
on wearing clothing. Now -10 achieves a windchill advisory. A recent day
(with a windchill advisory) when the windchill in Philadelphia got to
about -10 to -15 F felt the worst to me since a day in 1994 when the
windchill on the old scale was in the -40's F.

- Don Klipstein (don@misty.com)
 
I read in sci.electronics.design that Spehro Pefhany <speffSNIP@interlog
DOTyou.knowwhat> wrote (in <diiqv01ddv8hbiamu4fvbn0nulbm8tnrpe@4ax.com>)
about 'Wind chill', on Sun, 30 Jan 2005:
What's the equivalent in Phoenix? Minutes to fry an egg on the sidewalk
in midsummer? ;-)
Click to expand...
No. Midwinter.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
 
Content-Transfer-Encoding: 8Bit


Spehro Pefhany wrote:

I took the dog for a walk at night a week or two ago- the wind was
~20-30mph and temperature -22°C (-8°F). Taking a glove off to use my
Maglite and bag the leavings, I wasn't across an open field diagonally
before all the feeling was out of my little finger in that hand. Wind
chill is real enough!
Click to expand...
I really ought to mention that it has been between 72 and 75
degrees here in Los Angeles all week... :)
 
On Sun, 30 Jan 2005 12:44:06 -0700, Jim Thompson wrote:

<snip>

I always seem to have business back east at the worst-weather times of
the year... Pittsburgh on Wednesday :-(
Click to expand...
Better than Pittsburgh last Monday. That must have been a depressing
place! ;-)

It's cold here today... a cold front with rain came thru yesterday
afternoon... it's only +60°F, +15.5°C, here ;-)
Click to expand...
It's hotter than hell here today. It got to 27F (-2C for the
Canuckistanis here), and there was a big bright thing in the sky. We're
kinda wondering what it was, but it left about 5:00PM.

--
Keith
 
Howard Eisenhauer wrote:

Anybody know of a circuit to measure wind chill? I'm guessing the
best/simplest/cheapest way would be to measure how much current it
takes to keep a resister at certain temperature while exposed to Ma
Nature's little tantrums but I really don't feel like getting into a
theoritical design/prototype/troubleshoot/revise/build/yadda yadda
yadda project on this. Something I could get built & calibrated
before next summer would be nice- by next week would be fantastic
:).
Click to expand...

Thanks to all who replied. After reading thru the various responses
I've reached the conclusion the simplest solution to the problem is to
stay inside :).

Howard.
 
In article <22hqv0lslo9p9hnkciobbeuon180d7vld8@4ax.com>,
jmeyer@nowhere.net says...
On Sun, 30 Jan 2005 11:48:50 -0700, Jim Thompson <thegreatone@example.com
wroth:

On Sun, 30 Jan 2005 17:15:30 GMT, James Meyer <jmeyer@nowhere.net
wrote:

On Sun, 30 Jan 2005 14:54:36 +0000, Guy Macon
_see.web.page_@_www.guymacon.com_> wroth:


So why is it so popular? It makes the weather report on your local
TV station more exciting.


That's been my take on wind chill from the beginning.

Jim

Eh? Never been in Detroit this time of year have you ?:)

...Jim Thompson

Nope. Never been in Arizona at any time either.

Wind chill as a number that means anything is ridiculous. If you know
the air temperature and the wind speed you know enough. You don't need a
formula to tell you that the faster the wind blows, the more uncomfortable you
may become. And what about humidity? That's a large factor in how comfortable
or uncomfortable you may be.
Click to expand...
Wind chill was originally meant to express how rapidly uncovered flesh
would freeze. It's since been hijacked into a "touchy, feely" number
that does include humidity (e.g. Accuweather's "real feel").

Tell me the temperature, the wind speed, the humidity, the precititation
(if any), and I'll know what I need to wear and do to feel OK. I don't need a
fictitious wind chill number.
Click to expand...
It's not fictitious. Though I agree, I listen to wind-speed far more.
At -30C (as it was last week), I was happy to hear that it was dead
calm (even the wind was frozen ;-).

--
Keith
 
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