On Friday, 22 September 2017 01:22:14 UTC+1, mike wrote:

OK,
Let's go back to engineering 101.
What's the VERY MOST important part of a project?
It's the SPECIFICATION.

Exactly, precisely, concisely, unambiguously, completely stated
requirements.
This does NOT change. If you change your mind and change the spec,
you start a new project.

How do you know when you're done? You write acceptance criteria.
Exactly how the user, in this case you, is going to test the unit
to determine if you met the spec? If it passes the written acceptance
criteria, you succeeded. If it passes the test criteria, but doesn't
work, the specification was the problem. You get paid for this project
and start a new one with new specifications.

I can't emphasize how important the specification is. It's the number
one cause of project failure. You can't design for criteria that
were not specified.
It's easy to say, "I know what I'm designing for me...I don't need
no stinkin' specification." You'd be wrong. This thread is what you
get. Lots of rocket scientists when you really need a boat.
The very last place you want to discover that your forgot some
important requirement is when the completed device is deployed.

Words like exactly, "as good as possible" have no place in a specification.

Specs are numbers and test methods. Specs include allowable
variations due to initial component tolerances, component age,
temperature, vibration, misuse.
An example of misuse is, "what happens when the user hooks it
up backwards." I learned about vibration when I carried a
voltmeter on my motorcycle. When I needed it, it failed.
I took it apart and it poured out like sand.

The engineer doesn't need to know WHY you want what you want.
That's not his job. HOWEVER...if you state your objectives,
why you want to do this, you might find the bevy of rocket scientists
have a much better way to accomplish your objectives. I can't
count the number of times a user wanted an complicated gizmo,
but his objective could be achieved with a much different
and much simpler approach by repartitioning the system.

End rant.

He's making a one off for use at home, not commissioning a new design of military hardware.


First question I'd ask is, "are you gonna' stare at the meter 24/7?"
If not, get a cheap digital panel meter off EBAY, put a push button
in series and be done with it.

not compliant with the spec


NT