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Temperature measurement

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Carl Swanson

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May 14, 2003, 4:07:39 PM5/14/03
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Anyone have a way to measure temperature and broadcast it back to a
central location like a computer? Maybe something like X10 control
could do this, maybe not. I see remote temperature
guages all over the place now a days, either through wire or through
remotes. Either would work for me. But I want to monitor
a few locations, like my attic, basement, garage, house, outside, etc,
and then record it to the computer to track it over time.

Thoughts? Am I just dreaming?

Carl

anthony wooldridge

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May 14, 2003, 4:55:20 PM5/14/03
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"Carl Swanson" <cssw...@yahoo.com> wrote in message
news:404bed44.03051...@posting.google.com...

Check out dallas 1wire sensors, I think its DS1821 from memory, you can
string a load of them on a single twisted pair over a fair length.You can
read them via the serial port of a PC, or a microcontroller.
For true wireless transmission check out license free 433Mhz
transmitter/receiver modules. I have used them over about 1km line of sight
successfully at low data rates.
I used the Quasar FM range.
You can get them in 868MHz too but they are normally shorter range.

Anthony


the Wiz

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May 14, 2003, 9:20:17 PM5/14/03
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www.phanderson.com has some kits that use the Dallas ds182x 1-wire temperature
sensors. The kit supports a lot of sensors (256?) but there's a practical
restriction of 25 or so because wiring limitations.

Their server wasn't on-line when I wrote this message, so you may want to check
it in a day or so.

cssw...@yahoo.com (Carl Swanson) wrote:

More about me: http://thelabwiz.home.mindspring.com/
VB3 source code: http://thelabwiz.home.mindspring.com/vbsource.html
VB6 source code: http://thelabwiz.home.mindspring.com/vb6source.html
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johnecarter atat mindspring dotdot com Fix the obvious to reply by email.

Jem Berkes

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May 14, 2003, 9:37:06 PM5/14/03
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How about an LM335 (or 135, 235) precision temperature sensor?
http://www.national.com/pf/LM/LM335.html

Rather inexpensive as I recall. With just a resistor connected it can give
you an output linearly dependant on temperature. Just hook up a few of
these through a multiplexer or whatever to an A/D converter and read
through PC parallel port for instance.

--
Jem Berkes
http://www.pc-tools.net/
Windows, Linux & UNIX software

Dave Schoenwetter

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May 14, 2003, 10:04:10 PM5/14/03
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I use the Dallas 1 Wire and software
from:http://www.sunpoint.net/~thermometer/
It's been up and running over a year now and still working great. It
messages my CellPhone if temperatures are out of limits.
Dave


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Tweetldee

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May 14, 2003, 10:28:00 PM5/14/03
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"Jem Berkes" <j...@users.pc9.org> wrote in message
news:Xns937BD1C981A...@205.200.16.73...

Take a look at the USB interface DAQ system at
http://www.labjack.com/labjack_u12.html. It's a bit pricey at $119 US but
it will certainly do the job for you. All you would need to supply would be
the temp sensors, which, as Jem posts, will finish the system.
There are other DAQ systems available, at lower prices, such as the analog
input module at http://www.weedtech.com/ for $69.00 US. Again, all you need
to supply would be the sensors.
Both of the above DAQ systems come with software to get you started.
Search around on Google for 'analog data acquisition module' and see what
you come up with.

--
Tweetldee
Tweetldee at att dot net (Just subsitute the appropriate characters in the
address)

Time is what keeps everything from happening all at once.


Don Stauffer

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May 15, 2003, 9:47:08 AM5/15/03
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Simplest one I've seen is a thermistor in the circuit of an audio
oscillator, the output of which goes to the MOD input of an FM
transmitter, one of these small cheap things. Audio tone is function of
temperature. You need some form of conversion to frequency to something
in receiver. How about a frequency to voltage converter after
receiver. The system can be calibrated to give voltage as function of
remote temp.

--
Don Stauffer in Minnesota
stau...@usfamily.net
webpage- http://www.usfamily.net/web/stauffer

the Wiz

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May 15, 2003, 1:32:04 PM5/15/03
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Dataq has the DI-194RS, a 4 channel serial-port-controlled analog data
acquisition "starter kit" with monitoring & logging software (and info on
writing your own) for $24.95. The device is powered from the serial port.
http://www.dataq.com/194.htm

If you (or an interested friend) program in VB or VC++,
http://www.ultimaserial.com/ has an ActiveX control (shareware $25) that
provides even more features for the DI-194RS, including using the 2 digital
input lines as outputs. You could use these to control a switching matrix and
expand the 4 inputs to 16.


cssw...@yahoo.com (Carl Swanson) wrote:

More about me: http://thelabwiz.home.mindspring.com/

Chuck Yerkes

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May 18, 2003, 2:29:48 AM5/18/03
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Once upon a time, I learned FORTH.
The prof had a couple Apple ]['s (not new, but not too old).
The GAME PORTS are A/D converters.

He had them brought out to the front of the computer to 1/8 jacks.
He had a festival of sensors, often in BIC pens, with wires
for those jacks. Temp, photo-resistor, photo-transistor, etc.

You WROTE to one location and read back a number between 0 and 255.
Kinda cool with the phototransistor showing black for 2/3 readings
working late at night. Couldn't find the bug with my program.
Of course it worked with him there the next day. Failed that night.
Then he said "Are you running it with the fluorescents on?"
Yes...
"well that's it. Fluorescents flash - it's dark in here much of the
time."


1Wire may meet your needs. LM34's and LM35s may too ( 0.1V/degree
C (lm34) or F (lm35)).

But a basic A/D and any thermistor will do.

I also have some RS-232 temp sensors from a while ago (wiztemp, RIP).
RJ45/RS232 can run FAR for these.

1wire is likely cheapest.

simon

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May 19, 2003, 5:45:28 AM5/19/03
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see i2c-2-pc adapator at:
http://www.i2cchip.com

the adaptor gives an RS232 and USB interface to I2C,SPI and Dallas
1-wire devices, so you can connect to almost any a-d, temp sensors
etc.
Apart from the Dallas 1 wire sensors, the I2C type LM75 and
equivalents from national,texas,maxim and others, are cheap, and you
can hook 8 to a bus, and 24 per adaptor.

Rick Caldwell

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May 30, 2003, 8:16:18 PM5/30/03
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You might check out http://www.itwatchdogs.com/ or
http://www.weathershop.com/temptrax-E.htm

"Carl Swanson" <cssw...@yahoo.com> wrote in message
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Mitch

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May 31, 2003, 4:16:10 AM5/31/03
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Or http://www.midondesign.com/Temp05/TEMP05.html...

"Rick Caldwell" <ri...@dallas.geoquest.slb.com> wrote in message
news:bb8s8...@enews1.newsguy.com...

Watson A.Name - 'Watt Sun'

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May 31, 2003, 1:33:24 PM5/31/03
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In article <bb8s8...@enews1.newsguy.com>, ri...@dallas.geoquest.slb.com
mentioned...

No, not a dream. I would simply get a couple hundred feet of twisted
pair, could be telephone wire, or maybe even cheaper, thermostat wire,
since it's dealing with temp. Then solder a thermistor to the end at
the location where you want to monitor, and insulate with heat shrink.

If you use thermistors that are in the 30k to 100k range, they would
work as a replacement to the two pots in a joystick, which plugs into
the PC's game port. With two joystick inputs, that's four pots or
thermistors. Software would do the rest.

Here's another way of doing it with a serial port. But it's only good
for one thermistor. http://users.auth.gr/~mixos/projects/nopcb/pc/006/

There are other ways of doing it, you can find many systems for eneergy
management, HVAC, etc. It all depends on how much money you want to
spend.


> > Carl

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Michael

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Jun 2, 2003, 8:04:50 AM6/2/03
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Hi Carl:

Take a look at iScape Monitrol kit:

http://www.iscapecorp.net

You can measure as many temerature points as you like.
It uses RS485 network and DS1820 to measure temprs.
You can record 20k samples over time. And It doesn't
cost you much.

Michael


cssw...@yahoo.com (Carl Swanson) wrote in message news:<404bed44.03051...@posting.google.com>...

jl

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Jun 2, 2003, 5:31:22 PM6/2/03
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Sounds interesting...but that link is dead.


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BruceR

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Jun 2, 2003, 5:49:40 PM6/2/03
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Working today.

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jl

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Jun 2, 2003, 7:38:39 PM6/2/03
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It's back up


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Hrvoje

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Jun 5, 2003, 5:06:09 AM6/5/03
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DS1820 is great for temp measurements,and similar
"simon" <623...@despammed.com> wrote in message
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Edward Cheung

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Jun 14, 2003, 3:09:41 PM6/14/03
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Regarding DS1820s, there is a known issue with their calibration on
older units. I have encountered this inaccuracy personally in the units
I use.

http://www.brianlane.com/ds1820-report.pdf

Hrvoje wrote:

Edward Cheung
http://www.edcheung.com


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