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| Author |
Message |
rcurl
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Data Loggers
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Feb 24 17:14 UTC 1997 |
Hardware and software for data logging with computers.
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| 14 responses total. |
rcurl
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response 1 of 14:
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Feb 24 17:24 UTC 1997 |
I would like to log voltage over a period of ca. a day be means of
my computer. What is available, or what can I build, for doing this -
with a Mac, in particular. (I am looking in _Nuts and Volts_ at
an advert for the "LPT:Analog!", a PC printer port A/D adapter, which
is built into a DB-25 connector, which looks like what I want, except it is
only PC compatible.)
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n8nxf
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response 2 of 14:
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Feb 24 22:20 UTC 1997 |
That's why I also have PCs. There is a lot you can do with the parallel
port on those things. It's also easy to write Basic routines on a PC.
The only thing I know of for the Mac is something made by National
Instruments. Very expensive, as I recall.
In all honesty, this sounds like a good task for your XT.
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scott
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response 3 of 14:
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Feb 25 02:09 UTC 1997 |
You could try using the voltage to control the amplitude of an audio signal,
then feed that into a sound card...
I was looking at a new Jameco catalog at work today. They had a nice
selection of stuff, probably all PC based.
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arthurp
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response 4 of 14:
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Feb 25 05:06 UTC 1997 |
The sound card idea is cool.
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rcurl
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response 5 of 14:
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Feb 25 08:00 UTC 1997 |
....back to the XT....amazing. But, I don't think I can get a sound card for
the XT.... Klaus, do you know of any other A/D like the LPT:Analog!, even
a kit? I'd think there'd be a chip that would do all this, and some
free/share-ware to run it. I've also thought that it should be easy to include
a parallel interface in a multimeter, but I haven't seen one offered.
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n8nxf
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response 6 of 14:
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Feb 25 15:18 UTC 1997 |
Yes, you can get a sound card in an XT. At least an 8 bit unit... Don't
try it thoug. The input to a sound card is AC coupled and it won't see
a DC voltage, or low freq. AC.
Scott had a good suggestion with Jameco. They have several kits, one of
which may well meet your application. As I recall, they also had several
digital multimeters with serial ports. I think Radio Shack also sells a
multimeter with a serial port. Both should run with your XT and may come
with the required software. I don't have the Jameco catalog with me today,
though I placed and order with them yesterday... Perhaps scott, etc. has
their phone No. handy.
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rcurl
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response 7 of 14:
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Feb 25 18:01 UTC 1997 |
Yes, RS's "top" (and top $$) multimeter does have a PC interface (though
it doesn't take power from it for long term use). Actually, I wouldn't mind
having it - could use a multitester for C and L, at times. I'll check out
Jameco - probably they have a web site. Is there a "Stamp" application for
A/D conversion? I don't have the list.
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n8nxf
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response 8 of 14:
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Feb 25 19:19 UTC 1997 |
I think you could do it with a "stamp" too. I have wanted to fool with
one of those things, but have not yet found the time or a project
important enough to justify the time ;-)
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rcurl
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response 9 of 14:
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Feb 25 22:25 UTC 1997 |
Well, here it is - an A/D interface to a Mac for you and me.. 8^}
Jameco is on the web - in fact, their catalog is on the web. They have
meters with PC interfaces at about the RS cost. Did not see anything
more elementary, although there is a "microprocessor A/D chip" at a
reasonable chip-type price. MIght be the basis for...something...
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gull
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response 10 of 14:
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Feb 26 06:43 UTC 1997 |
You can get an 8-bit A/D interface for a PC for under $20.
They're sold as 'joystick ports.'
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rcurl
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response 11 of 14:
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Feb 26 07:04 UTC 1997 |
Any instructions on how to adapt that for data logging? I vaguely recall
seeing such written up (maybe in _Nuts and Volts_) but have no references
to it. That's the sort of thing I'd like to find. I suppose I could write
a BASIC program to do the logging (gosh, I used to know how to do that!).
Hmmm... probably something out there on the web, under home automation,
for those that record temperature, light intensity, etc.
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gull
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response 12 of 14:
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Feb 27 03:00 UTC 1997 |
I think the biggest trick would be inputting the signal to the card -- it
expects to be measuring the resistance of the joystick's pots. The cards
generally have four channels, X and Y for two joysticks; plus four on/off
switch inputs. Most programming languages, including BASIC, can access a
joystick card one way or another. I have a joystick port pinout somewhere
if you need it, I'd have to dig it up, tho.
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rtgreen
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response 13 of 14:
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Mar 1 23:02 UTC 1998 |
The PC joystick interface measures the time it takes to discharge a
known capacitor through the resistance of the joystick pot. It's not
straightforward to condition a voltage to look like a resistance.
Easier to go the other way...
Do you have an old Commodore VIC-20 or C-64 laying around? The
built-in joystick port on those machines is a real 8-bit a/d measuring
0-5v directly. A simple voltage divider can adapt it to higher
voltages, and the port is easily read by the builtin BASIC interpreter.
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arthurp
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response 14 of 14:
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Apr 15 04:48 UTC 1998 |
Hmm. I'm interrested in the same kinds of use of the joystick port. It
has so be on a PC, though. Any further developments?
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