Pasted

so these two guys are having lunch at the worksite
pisse dher off, oh well nothing new
one of them is chuckling to himself, the other asks whats so funny
he says "aw, man, I had the most embarassing Freudian Slip last night"
the other guy says "what the hell is a Freudian Slip?"
"it's when you accidentally say what you're thinking about, instead of saying what you're talking about"
he gets a blank stare, so he  says "OK, so last night, I'm taking the subway home"
and the lady at the ticket counter has the biggest tits I've ever seen. enormous. I couldn't stop staring"
"so when it gets to my turn, I meant to ask for my change in nickels"
"instead I asked for my change in nipples"
lololol
they both laugh and the other guy says "Ok, ok, I think I get it... I had one of those last night too"
I'll take the nipples
"I was at the dinner table with the family, and I meant to say 'honey, please pass the salt"
"but instead I said "BITCH YOU RUINED MY LIFE"
oooo tough crowd
I guess it's better delivered in person?
OMG I've wanted to say something like that soooo many times over the past 39 years.
lol
Yet I would say what the frack did you get yourself into? Well Got a good cook out of the deal anyway.
lol
OK, have you ever seen the inside of a stepper motor?
Did I show you those pics?
yes
ok, you remember what makes them different from normal motors
what happens when you apply a constant current to a NON-stepper motor
magnets
lol bingo
spinning magnets
normal motor + electricity = spinning
+-+-+-
stepper motor + constant electricity = ?
(hint: from "off" to "on" would be one step)
positive switches to negative and vice versa
Yes
and in a big motor with only a few poles, that's a relatively large rotation
in a stepper motor, it's a small movement, but very precise
now, how do we know how many steps a motor has in one revolution?
By telling it what it is suppose to do
you're one step early, I think
The number of steps in a rotation is a physical property of the motor... like the gear ratio in a differential
no matter what settings you change, how much voltage you apply, the number of steps you need to send to that motor to get one rotation does not change
now, with some fancy footwork, we can create "pretend" steps in between the real ones
it's just the speed of which it reaches that full rotation
I think so... your wording is different, but it sounds like you follow
So a stepper motor makes steps. There are a fixed number of steps in a rotation, so each step has a fixed step angle
if you have a 200-step motor, and you send 200 steps in half a second, and then 200 steps over ten seconds
okay, sorry, step Angle?
yes
don't apologize, this is good feeedback for me
imagine a staircase
rise height
you like to build shit, this will be a good analogy
you have to go up 40'm
sorry
40'
and you have to build exactly 48 steps
assuming they're all the same height
how tall is each step?
10 inches per step
bingo
now
this is going to be the most useless staircase every
lol
you have to go up 30'
and you have to build exactly 200 steps
how tall is each step
might as well just build a ramp, 1.8"
now, imagine that same staircase as a ladder instead
one rung every 1.8"
now wrap it in a circle
the whole ladder is 360 degrees
and there are 200 steps
each step is 1.8 degrees
so the step angle is 1.8 degrees
was that helpful?
okay.for now it's in there.
lol, okay
now every time you send a pulse to the motor, it turns one step
so in this example, it turns 1.8 degrees
right
if you send 100 steps, how far does it turn?
half way
bingo
ok, now we need to translate that ladder into the little black boxes on your printer
if you send 100 steps to the motor, the shaft will turn one-half rotation
you still with me?
so if there are 200 steps in a revolution and one revolution travels 5mm then you would have 80 revolutions in a 400mm x travel. Please be right
that is correct
but
only if the motor travels 5mm in one rotation
ours do not
but that statement is correrct
*correct
I see where your confusion lies
I'm going to re-word your statement
in pieces
with one small but critical change
if there are 200 steps in a revolution
and one STEP travels 5mm
then 80 STEPS
would travel 400 mm
would be 400mm
does that make sense?
'yep
ok, now
the reason you got mixed up there
is becuase you jumped a step
we need to translate step ANGLE into step DISTANCE
now, we don't have to think about diameters or pi or any of that bullshit
because we know two things
I don't know pi that's one
sorry
1) we're using a toothed belt with ONE tooth every 2 mm
and 2) the pulley on our motor has EXACTLY 20 teeth
okay
so
if we rotate our motor one HALF rotation, how far does the belt move?
sorry
20mm
imagine there's a black line on the face of the motor, from the centre of the shaft to the middle of one edge
like this
so you need to know the radius too?
Of the pulley?
nope
one sec
k
phew
that was stressful to pull of quickly
now
that pulley on the motor has 20 teeth
and before we send any signals, the red one is lined up with the black line
still with me?
yep
ok
now, we send 100 steps
how many teeth go past that black line?
ooooh you're overthinking it
I can tell
back it up, how many teeth on the pully total?
20 each 2mm aaprt
yes!
okay, now how far does the shaft rotate with 100 steps?
half way
yes!
ok, now, if the pulley is GLUED to the shaft, 1:1 movement, no questions, how many teeth have rotated past that black line after 100 steps?
50
whoops
try again
noooooo 10
YES!
now, how far apart are the teeth on the belt?
2mm
so how far has the belt moved after 100 steps?
20mm
YES!
NOW
Now, how far does the belt move for 10 steps?
2mm
fucking yes
now
how far does the belt move for one step
.2mm
oh my god, almost there
now
how many steps to move one mm
5
ladies and gentlemen, I give you
steps /mm
phew
I enjoyed that
OMG, I need to copy and paste this to my notepad.
LOL
take your time, I need a cigarette
I'm kidding I don't smoke
same here, more like a mouthful of nicorrete
Have a shot of scotch on me.
damn straight
let me know when you're ready to continue
WHAAAA, ALOL
go for it
Did you get all that copied?
No will do it later can only copy and past one message at a time. takes too long