magnetic field

"mark thomas" <marycoy4@execyulinky.comy> wrote:

3) Ground the weather station AND use fiber optic cabling

Yeah, do that one. Yes, more work, but far more safe. Lightning
striking an ungrounded/unprotected weather station will find it's own
path to ground (through the power supply, the foil insulation on your
house, the wood, the bedroom, whatever) instead of taking the
preferred one thru the ground wire to a safe ground point.

 

[CWatters]

"mark thomas" <marycoy4@execyulinky.comy> wrote in message
news:X62dnVJkX9pSAiHcRVn-uA@golden.net...

I'm building a weather station that connects to my computer via RS232.
The
problem is I'm worried about my computer being damaged if it gets hit by
lighning, I don't want the lighning conducting through the RS232
cabling...
A few questions...

You are right to be concerned as PC RS232 ports are quite vunerable to
static damage.

Opto-isolators are the answer.

Google found these expensive solutions. I didn't spend time looking for
cheaper ones..

http://www.rs485.com/fullphotos/iso232wbfull.html

http://www.meilhaus.com/e_me/me9100.htm

http://www.elandigitalsystems.com/interface/ic232.php

 

[CWatters]

"mark thomas" <marycoy4@execyulinky.comy> wrote in message
news:b4KdnfwobMUqUCHcRVn-2A@golden.net...

The artist formerly known as Jim Thompson wrote:

| An ordinary opto-coupler WILL NOT BLOCK LIGHTNING! Most are perhaps
| good to 3000V.

Not really expecting optos to protect against a direct strive. A direct
lightening strike is unlikely and if you get one of those you will have
bigger things to worry about

A more likely problem is "nearby" strikes or simply as build up of charge
due to a passing storm. Opto provide a good solution for that. If you are
thinking of using fibre you need to work out how you are going to power the
station. A solar cell and a battery maybe the answer.

 

[CWatters]

<brownyear@yahoo.com> wrote in message
news:1102938452.901620.239760@c13g2000cwb.googlegroups.com...

Intrested in using an standard Compressor from an refrigerator or an Ac
air conditioning system for producing all kind of special
effects .
For example sounds , waves etc .

Not sure about sound effects but try these pages...

http://www.clubhyper.com/reference/compressorgi_1.htm

I'm more familiar with this application...
(Scroll down for diagram)
http://users.pandora.be/Toothless/Toothless/pages/instructions/vacuum/vacuum.html

Some people have used fire extinguishers as pressure reservoirs.

You must use a safety valve or BOOM!

 

https://www.sierraic.com/datasheet.asp?part=DT28F160
Try this website www.sierraic.com
free access to 9 million datasheets
Thank you,
Joe

 

[Dave VanHorn]

Martin Uman's books make good reading, though he's mostly concerned with how
lightning happens in the first place.

 

[Franc Zabkar]

On Sun, 12 Dec 2004 13:45:43 -0800, "Watson A.Name - \"Watt Sun, the
Dark Remover\"" <NOSPAM@dslextreme.com> put finger to keyboard and
composed:

If you had the old original true IBM 8-bit ISA RS-232 card, it
had built-in current loop which had the opto's already on the board.

Which one was that?

The IBM AT Tech Reference manual has a circuit diagram of the
serial/parallel adapter. It used 75154 and 75150 transmitters and
receivers, but no current loop. I repaired many of these cards where
the interface chips (and some UARTs) were taken out by lightning.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

 

[Roger Johansson]

"Phantoz" <phantoz@hotmail.com> wrote:

atm), as well as that the device allow the student to choose one of
four options, and work at an acceptable range (say, 20-25 meters). I
would like to translate the results real time to some comodity pc
hardware.

Why do you need radio communication for distances of 25 m ?
A network of computers and a simple program is a lot easier, and the
students already have laptops, I presume. (The pupils get free laptops
to use in the schoolwork when then begin school at 6 years age in my
country, and all classrooms have networks built in already)

The simple function you described can be realized with a simple directly
wired circuit, if the students have no laptops. Hardware cost is
something like 100 dollars.

In short, forget the radio communication, it is extremely unnecessary for
the purpose you describe. We are trying to minimize non-important radio
communication, because there is too much pollution of the radio frequency
ranges.


--
Roger J.

 

[CWatters]

"Gary Schafer" <gaschafer@comcast.net> wrote in message
news:fcnvr05cmkmppqmkvrkhm9obklco0glcqf@4ax.com...

Try garage door openers. You can program multiple codes in them and
they are available with multiple functions.

One student with a finger on the button would probably block all the other
transmissions.

 

[CWatters]

"Phantoz" <phantoz@hotmail.com> wrote in message
news:10ruufnfl8q9ve9@corp.supernews.com...

Hi,

I'm in a situation where I would like to buy (or build, prefferably the
former since I have little to no skills in electronics) a large number
(perhaps few to start with, but scaling up to 100 or so) rf
receiver/transmitters.

Mobile phones? Text 1,2,3,or 4 to this free number etc...

Do a deal with the phone company for special rates to that phone number.

 

[Wim Ton]

We had that problem with a system in two adjacent classroms operating in
the
same band.
You have to make sure you are not in close proximity to a garage opener
testing ground.

Use IR ?

Wim

 

[Watson A.Name - \"Watt Su]

"Rich Grise" <rich@example.net> wrote in message
newsan.2004.12.12.09.35.28.215148@example.net...

On Sun, 12 Dec 2004 02:04:37 +0000, Clarence wrote:


"Watson A.Name - "Watt Sun, the Dark Remover""
NOSPAM@dslextreme.com> wrote in
message news:10rn9fflrpf0f54@corp.supernews.com...

"Sylvan Butler" <ZsdbUse1+noZs_0412@Zbigfoot.Zcom.invalid> wrote in
message news:slrncrmlu4.nhg.ZsdbUse1+noZs_0412@knoppix.internal...
On Sat, 11 Dec 2004 04:42:48 -0800, Watson A.Name - "Watt Sun,
the
Dark Remover" <NOSPAM@dslextreme.com> wrote:
What's unfortunate is that the "doomsday scenario" has already
happened.
I suggest you read this.
http://www.pbs.org/now/politics/walmart.html

Do you believe everything you see in a television documentary?
Or
just the documentaries on PBS?

If you had read the article, you would have found that they are
referencing articles in the New York Times, Time Magazine, among
several
others. Read it.

I did. Very positive! Seems they are a success, and therefore are
being
attacked by those jealous of that which they can not achieve.

Interesting!

Not jealousy. Envy. Jealousy is fear of being replaced. Envy, however,
has
shown since time immemorial to be a very, very powerful political
tool.

Cheers!
Rich

I think he's trying to push on a rope. Attacked? Gimme a break.
Jealous or envious? Gimme a break. More like they cannot (or will not)
achieve what Giant Company is achieving by illegal and unethical means.
That's what the articles point out. But then he's too blind to see
that. I'm wasting my time, talking to a tree. (/ent)

 

[Paul Burridge]

On Wed, 15 Dec 2004 20:49:55 GMT, Rich Grise <rich@example.net> wrote:

I suppose the entire HVAC industry will have to refund all of the money
for all of those filters and electrostatic precipitators and ozone
generators that people have paid so handsomely for, that the FTC has
declared by fiat, don't work.

I guess it's been decided by the government that the only way to get
healthy indoor air is to ban smoking, and that dust mite feces,
bacteria/virus/fungus spores, outgassing construction materials, human
effluvia, and so on have nothing to do with it.

Do you actually get much of a problem with mosquitoes in the US? I'd
always thought of them as most associated with the tropics...
--

"What is now proved was once only imagin'd." - William Blake, 1793.

 

[Watson A.Name - \"Watt Su]

"Chuck Harris" <cf-NO-SPAM-harris@erols.com> wrote in message
news:VuSdnbKvLN-ALFzcRVn-hg@rcn.net...

Paul Burridge wrote:


Do you actually get much of a problem with mosquitoes in the US? I'd
always thought of them as most associated with the tropics...

We are getting more and more problem all the time. The Greenies have
decided that we need to sprout up "wetlands" everywhere new
construction
happens. To do this, they force developers to put in elaborate
holding
ponds/swamps for storm water runoff. These ponds/swamps are the
perfect
breeding ground for mosquitoes.

In other areas, they have increased the amount of wetlands by raising
the drainage culverts for driveways and small roads 6 inches, or so,
above the ditch bottoms. This is supposedly to slow down the runoff,
and make mini drainage ponds that allow the storm water to soak in.
What actually happens is mini swamps that harbor mosquitoes are
formed.

In Virginia, a small outbreak of malaria was recently reported. The
vector is believed to be a small group of illegals from Mexico that
were found to harbor the disease. They were working as landscapers
on a mosquito ridden island, and infected the local crop of
mosquitoes.

All through the East Coast, West Nile disease is starting to flourish.
Crows, which are very vulnerable to the disease, are dropping from the
sky. I have several friends who have contracted the West Nile
disease.
It wiped out about 4-6 months of their lives while they combated
extreme fatigue and bouts of confusion.

Since DDT is banned worldwide, and there is nothing as safe or
effective
to use as a substitute, it is just a matter of time before the US has
problems with yellow fever.

But that really doesn't matter, because the little duckies have a
place
to swim.

-Chuck Harris

You make some valid points, but it should not be implied that because of
the diseases, we should wipe out the habitats of other animals. After
all, wiping out the disease itself, or its vector, the mosquito, is
really the solution. DDT did wonders for eradicating malaria and those
fevers in africa, but we all know that when it got into the food chain,
it did serious damage. So perhaps it's better to use something like
this (see URL below) to catch the skeeters, instead.

Wow, 176 species of skeeters in the U.S.! Read the last paragraph for a
quick summary of the methods used to control skeeters.

http://www.mosquito.org/MosqInfo/Traps.htm

 

[Jim Thompson]

Anyone know about those devices that generate a CO2 fog, attracting
the mosquitos and then "vacuums" them into a trap?

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Cyli]

On Thu, 16 Dec 2004 14:47:42 +0000, Paul Burridge
<pb@notthisbit.osiris1.co.uk> wrote:

(snipped)

Do you actually get much of a problem with mosquitoes in the US? I'd
always thought of them as most associated with the tropics...

Yes. Minnesota, Land of 10,000 Lakes*, has mosquitos. Lots of
mosquitos. Much of Canada and Wisconsin and Michigan have, too. The
east coast of the US has them all up and down it. Alaska, hardly
tropical, is famed for them. Most of the states that have them seem
to make jokes about them being the state bird.

Here the are mainly a nuisance. They do spread some disease, but no
major problems, even with West Nile yet.

*Our motto, actually many more, along with ponds and swamps that
aren't counted.

Cyli
r.bc: vixen. Minnow goddess. Speaker to squirrels.
Often taunted by trout. Almost entirely harmless.

http://www.visi.com/~cyli
email: cyli@gmail.com.invalid (strip the .invalid to email)

 

[Bart]

In article <7va4s0pa47rk32coko6c6p1jhf3dp8br46@4ax.com>, cyli@visi.com wrote:

Yes. Minnesota, Land of 10,000 Lakes*, has mosquitos. Lots of
mosquitos. Much of Canada and Wisconsin and Michigan have, too. The
east coast of the US has them all up and down it. Alaska, hardly
tropical, is famed for them. Most of the states that have them seem
to make jokes about them being the state bird.

I wish ours were as small as birds.

Had to use my deer rifle on two of them today.
One had my Great Dane in a head lock while
the other tried to violate her!

 

[Tim Williams]

"Cyli" <cyli@gmail.com.invalid> wrote in message
news:7va4s0pa47rk32coko6c6p1jhf3dp8br46@4ax.com...

Yes. Minnesota, Land of 10,000 Lakes*, has mosquitos. Lots of
mosquitos. Much of Canada and Wisconsin and Michigan have, too.

Last summer was *very* light on mosquitoes. Almost none, only a few after
the occasional rain (was kinda dry too) here in S WI. Then again, with the
hot non-winter, I'm pretty sure those were mosquitoes I saw at the last trip
to the junk yard. Occasional groups a foot or two across buzzing above a
puddle or whatever, but what's unusual is in all my life I've never seen any
over 1/4". These were like 1/2"...

Tim

--
"I've got more trophies than Wayne Gretsky and the Pope combined!"
- Homer Simpson
Website @ http://webpages.charter.net/dawill/tmoranwms

 

[Chuck Harris]

Jim Thompson wrote:

As another poster said, purple martins are more effective.

-Chuck Harris


How about bats? The preserve behind my house has a large bat
population.

...Jim Thompson

No, I think purple martins only eat mosquitoes ;-)

-Chuck Harris

 

[Steve Evans]

On Fri, 17 Dec 2004 12:15:29 -0700, Jim Thompson
<thegreatone@example.com> wrote:

How about bats? The preserve behind my house has a large bat
population.

bats are perfectly harmelss, mr. thompson. levae them alone.
--

Fat, sugar, salt, beer: the four essentials for a healthy diet.