On Sat, 22 Mar 2025 06:28:35 -0400, zen cycle
<
funkmasterxx@hotmail.com> wrote:
On 3/21/2025 10:12 PM, Jeff Liebermann wrote:
On Fri, 21 Mar 2025 18:21:35 GMT, cyclintom <cyclintom@yahoo.com>
wrote:
Tell everyone here what the conduction is in a swimming pool leak you damned fool? The problem isn't that you don't need 24 bit doesn't mean you can even START to get by with 10 bits. What sort of idiot believes that fresh water is a strong conductor?
No such thing as "fresh water". Here are some common choices. Which
one were you trying to measure:
conductivity in micro Siemens per cm
Distilled water 0.5 - 3.0
Melted Snow 2 - 42
Tap Water 50 - 800
US Potable water 30 - 1,500
Freshwater streams 100 - 2,000
Industrial wastewater 10,000
Seawater 50,000
<https://atlas-scientific.com/blog/conductivity-of-distilled-water/>
For a time, I was the self appointed tester of water quality for a
small water district. It was nothing fancy. I was just trying to
determine if and when the local water district dumped something
disgusting into the redwood water tanks and ruined my coffee or tea.
For the purpose, I used an older version of a pH and TDS (total
dissolved solids) tester:
<https://www.google.com/search?q=tds%20tester&udm=2>
<https://www.ebay.com/sch/i.html?_nkw=tds%20meter>
Dirty or contaminated water has a higher conductivity. I could easily
tell when the water district dumped too much hydrochloric acid into
the water tanks. For drinking water, the EPA wants the TDS to below
500 ppm. Easy (and lazy) conversion between TDS and ppm.
<https://pureaqua.com/tds-converter-calculator/>
<https://pureaqua.com/tds-ec-conversion/>
Why do you have to continually have to prove that you're not a design engineer. That 24 bit A-D was designed into that product by by Charley Button who has several international design awards and you're stupid enough to tell us that you know more than he. All I did was program it to work.
What Tom is trying to measure is the conductivity to 24 bit resolution
(16,777,215 bits). Assuming the best case conductivity meter, with a
range of +15V to -15V DC, and with a 24 bit A/D, the 1 bit resolution
would be:
30 V / 16,777,215 = 1.79 microvolts per bit.
Besides taking forever to obtain a stable measurement, the meter would
require platinum probes, an elaborate bridge circuit and very low
noise differential input amplifier to obtain an accurate reading. I'm
not sure how to calculate the noise floor for such a precision device,
but my guess(tm) is that it will be very close to the thermal noise
floor. In other words, that means that the thermal noise will like
dominate the measurement causing the indicated voltage to bounce
around. Anyway, the design is overkill for a "leak detector".
The TDS testers previously mentioned have 4 decimal digits of display.
That would be 0 to 9999 ppm. Converted to binary, that would be
10011100001111 or 14 bits (which is much less than 24 bits). With +/-
1 digit (not 1 bit) uncertainty, 13 bits will suffice. If an
averaging feature is added to stabilize the measurement, then 10 or 11
bits will suffice.
All I did was program it to work.
Yep. Here's some sample code for a TDS meter using an Arduino UNO:
<https://docs.cirkitdesigner.com/component/bcc7adac-432b-4e03-b535-1c22aacb9f68/tds-sensor>
<https://www.electronicwings.com/arduino/adc-in-arduino>
The UNO has 10 bits of resolution over a 0 to 5V range.
Since the Arduino UNO was first introduced in 2010, I would not expect
the hardware and your code to have been that simple.
Oddly, I can't find any mention of this project on your online resume:
<https://www.linkedin.com/in/tom-kunich-22012/details/experience/>
>
Likely because he didn't actually do the work, of course that hasn't
stopped him from lying and embellishing what he did in the past, but as
you've noted there's a 20 year gap in his resume anyways.
The gap was between when he left the military in 1965 and when he
started his first job Jan 1984, a gap of 19 years. Tom was employed
at Berkeley Computer Corporation for and unknown length of time
somewhere between 1969 and 1972.
Considering that he wasn't aware what the hardware architecture was, it
would have been exceptionally difficult to program. He would have needed
to configure the uC to read the output of the ADC through one of the uC
inputs rather than use the integrated ADC. This is a rather significant
difference in bot the software and firmware architectures, and if he had
actually written the code it's highly unlikely that he wouldn't have had
some recollection of the whole exercise when he opened the file to
copy[paste it here:
>
"/*SuperSnoop Dectector Board
>
Operation of the Detector:
>
1. Via a Detector wand the board detects current
flow through the water. The current flow is via an AC source from the
Generator Board. This current flow is detected via the voltage drop
through the medium's resistance."
This is the first time I've looked at the description careful. I'm
finding some problem.
I don't know how to measure current flow with a "wand". The correct
term is a probe.
One does not "detect" current, which is by definition a threshold
measurement. A threshold detector would output an on or off signal
(one or zero) as set by a pre-programmed value. That requires a 1 bit
A/D converter, not a 24 bit converter.
It's not clear what is meant by a "generator board". Using AC to
measure a specific conductivity isn't going to work. The output
reading of the 24 bit A/D converter is going to vary between the AC
amplitude peaks giving a highly erratic and imprecise measurement.
Again, for current flow to be "detected" requires only a 1 bit A/D
output (also known as a switch).
Detecting the AC current flow through the "medium", which I presume is
the water, isn't going to work unless the resistance (actually the
conductivity) of the water is known. Unless Tom is measuring the flow
of distilled water or a well controlled chemical, it's not possible to
measure or detect the current flow.
With all the sources of error introduced by this amazing current flow
detector, it won't work or do anything useful. I see two choices
here. Either Tom doesn't understand how his "detector" works or the
device didn't function as expected and was discarded.
Rereading it now, (two years later) I have to admit my recent previous
statement was wrong - it does in fact measure the electrical
conductivity of water, not the current flow of the water itself (not
sure where I got the idea it was used to detect swimming pool leaks, but
hey, I didn't write it).
Probably. I don't want to look at the code to see what is actually
being measured. The "Operation of the Detector" description doesn't
seem to indicate what the "detector board" actually does.
That said, considering he also seems to think it was used to detect
swimming pool leaks based on _my_ misremembering, it's simply further
proof he had nothing to do with the project other than somehow having
access to the source code.
My assumption was that since he was measuring conductivity, and a
swimming pool was mentioned, he's either measuring pH, which does not
match the "operation" description or he's measuring TDS (total
dissolved solids), which does not require 24 bit resolution.
-- Jeff Liebermann jeffl@cruzio.comPO Box 272 http://www.LearnByDestroying.comBen Lomond CA 95005-0272Skype: JeffLiebermann AE6KS 831-336-2558
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