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From: "Jim Wilkins" <muratlanne@gmail.com>
Newsgroups: rec.crafts.metalworking
Subject: Re: boat propulsion - miniature computer-controlled steam plant?
Date: Sun, 10 Mar 2024 08:43:31 -0400
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"Richard Smith"  wrote in message news:m1r0giiqkd.fsf@void.com...

I have a "Fluke" meter with clamp to measure Amps - AC and DC.
Not the point - you are pointing to a project.

I did think of a device to measure voltage - get it to "stab" in at the
torch/gun - and have it speak the voltage so you can run the arc and
weld while having the info.
I bet there are voice devices for saying numbers?

GnuPlot will graph text files of data - my perception there is no need
to keep the data in other than text format.  A compression algorithm
like "bzip2" can get compress the files ot fractions of the former size
- so easy to keep data.

I've done sampling (?) before:
http://www.weldsmith.co.uk/tech/welding/datalog/datalog_weldproc.html
Welding - MIG/GMAW "waveforms" revealed by datalogging
Noting average-Amps x average-Volts does not give average-Power with
systematic pulse waveforms.

Arduino - I was rather delighted about "getting" that one.
Have programmed in "C" before, so head start.
Quickly extended beyond tutorials, using
loops "for..."
conditionals "if..."
to get more interesting things happening.
eg. LED's flashing morse-code
from tutorial getting an LED to light.
Hopefully this will stand as a "proof of concept" and be the start of a
progression - hopefully with the adjective "rapid".

----------------------------
Good, you understand the process and its value already. The other obvious 
use is a robot that crashes into walls and furniture, which is funny with a 
toy, less so with a heavy Segway bot. The perpetrator had to autograph the 
damage which was left as a reminder.

I use a laptop and DMMs with RS232 interfaces to measure and record battery 
charge and discharge. Since they use slow dual slope A/D converters their 
measuring rate is 1 or 2 per second, which is fine for a steady load, but 
too slow for the pulsed output of a solar controller. A digital storage 
scope captures a short sample of the voltage and current pulses for analysis 
though it won't integrate current into the battery charge level. For that 
dedicated battery power monitors serve well enough, at least for the steady 
discharge current. All do some, none do all.

The high price of commercial data loggers prompted me to consider building 
my own, which would operate at a much higher sampling rate than the DMMs. A 
Dataq starter kit sort of works but I prefer a higher resolution and 
interactive control. I had designed and built a fast 16-bit data logger card 
that plugs into a Macintosh for work, where they wouldn't allow IBM PCs 
after being embarrassed by a hacker. They gave it back when done and 
converting it to a printer port interface is on my to-do list. I have 
experience building and programming high end industrial measurement systems.
https://en.wikipedia.org/wiki/Automatic_test_equipment

Most of the measurements are performed by voltage and current controlled 
power supplies that report their outputs to the computer, as does this:
https://www.amazon.com/RD-Bluetooth-Step-down-communication-DPS5020-USB-BT/dp/B099ZJ1MZG

With battery discharge and welding the voltage drops from high current are a 
concern. You don't want welding current taking a short cut through the 
measurement leads. For the ATE we had to limit measurement and return lead 
currents to a few milliAmps.

That experience served me well when Mitre took up digital radio, which is 
much like a 2 channel digital oscilloscope. Unlike the radio engineers and 
techs I knew how to use high speed A/D converters and connect them to a 
TMS320C30 digital signal processor, I had designed an IC that let both use 
the same memory simultaneously. Digital radio was the enabler for cell 
phones.