PC monitoring of a DC signal

B

Bill Rule

Guest
I wonder if anyone out there has a sound no-frills way of monitoring
either a 10mV or 2V DC signal (at approx 1 to 3 Hz)using
shareware/freeware and taking the signal through either the Parallel
port or a sound-card?

Basic building of an appropriate black box wouldn't be beyond me, but
this is to temporarily allow the output from a UV detector on an HPLC
in a lab.

Cheers
 
On 24 Jun 2004 23:23:36 -0700, brule@netcon.net.au (Bill Rule) wrote:

I wonder if anyone out there has a sound no-frills way of monitoring
either a 10mV or 2V DC signal (at approx 1 to 3 Hz)using
shareware/freeware and taking the signal through either the Parallel
port or a sound-card?

Basic building of an appropriate black box wouldn't be beyond me, but
this is to temporarily allow the output from a UV detector on an HPLC
in a lab.

Cheers
Click to expand...
My Daqarta for DOS package will do this if you use the
LPTX driver. You will need to build a simple 8-bit ADC
from an R-2R ladder, which is driven by the LPT data port. The
output of the ladder is combined with the input signal
and applied to a pin on the LPT status port. The driver
takes care of switching the ladder and watching the
status bit to determine the input value. Depending
upon your particular LPT port, you may be able to do
this with just passive components. Worst case, you
may need to add a digital buffer (74HC373) to make
the data pins have equal drives. Schematics for both
designs are in the LPTX.HLP file.

Daqarta will allow you to monitor the signal in real-time,
and optionally save it to a disk file.

Sound cards don't go down to DC. If you want to use
a sound card, you can apply your signal to a "chopper"
to turn it into a square wave at a higher frequency
(say, 1000 Hz) that the sound card can handle, then
you can demodulate the envelope in software that
you will have to write yourself. (I'm working on this,
but it's a back-burner project.)

Hope this helps!


Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
 
brule@netcon.net.au (Bill Rule) wrote:

I wonder if anyone out there has a sound no-frills way of monitoring
either a 10mV or 2V DC signal (at approx 1 to 3 Hz)using
shareware/freeware and taking the signal through either the Parallel
port or a sound-card?

Basic building of an appropriate black box wouldn't be beyond me, but
this is to temporarily allow the output from a UV detector on an HPLC
in a lab.

Cheers
Click to expand...
How about $25US for a serial-port powered multi-channel A/D converter with
software?

http://www.dataq.com/index.html Click on the "Click Here" in the left column.

It also includes an ActiveX control for interfacing your own Windows programs to
the device (if you're a programmer ;-)

More about me: http://www.jecarter.com/
VB3/VB6/C/PowerBasic source code: http://www.jecarter.com/programs.html
Freeware for the Palm with NS Basic source code: http://nsb.jecarter.com
Drivers for Pablo graphics tablet and JamCam cameras: http://home.earthlink.net/~mwbt/
Email here: http://www.jecarter.com/contactme.htm
 
Well, I guess I can't go past that for a deal... thanks to you both for the
tips.

"the Wiz" <look@message.body> wrote in message
news:t0trd0pc9kf3qfvt5pmot14i8a6mh63uq9@4ax.com...
brule@netcon.net.au (Bill Rule) wrote:

I wonder if anyone out there has a sound no-frills way of monitoring
either a 10mV or 2V DC signal (at approx 1 to 3 Hz)using
shareware/freeware and taking the signal through either the Parallel
port or a sound-card?

Basic building of an appropriate black box wouldn't be beyond me, but
this is to temporarily allow the output from a UV detector on an HPLC
in a lab.

Cheers

How about $25US for a serial-port powered multi-channel A/D converter with
software?

http://www.dataq.com/index.html Click on the "Click Here" in the left
column.

It also includes an ActiveX control for interfacing your own Windows
programs to
the device (if you're a programmer ;-)

More about me: http://www.jecarter.com/
VB3/VB6/C/PowerBasic source code: http://www.jecarter.com/programs.html
Freeware for the Palm with NS Basic source code: http://nsb.jecarter.com
Drivers for Pablo graphics tablet and JamCam cameras:
http://home.earthlink.net/~mwbt/
Email here: http://www.jecarter.com/contactme.htm
Click to expand...
 
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