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Author Topic: Also having troubles with straight lines
RyanSchuij-
er
Newbie
Posts: 2
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RyanS
Post Also having troubles with straight lines
on: December 28, 2014, 22:57
Quote

Hello everyone,

Over the past few months I've been building a polargraph according to the Polargraph Instructable (a really marvellous one, thanks SN!)

The machine can draw now but everything it outputs is arc shaped, wide bottom.
So I saw another topic about this over here, which made me fiddle with the specs, especially the 'steps per rev' and 'multiplier' settings but I can't seem to get it right. I also saw your post on github regarding the distorted drawings. I tried to position the gondola higher or lower, narrowed the machine width and remeasure everything mm perfect but unfortunately no victory tune.

I am not really sure where to look for the solution so I hope you can help me!

Also specs:

Hardware
Adafruit Stepper Motors 200 steps/rev
Parametric Sprockets from John Abella

# *** Polargraph properties file ***
#Sun Dec 28 23:37:25 CET 2014
controller.pixel.samplearea=1
controller.pictureframe.position.y=232
controller.pictureframe.position.x=273
controller.testPenWidth.startSize=0.5
controller.machine.colour=969696
machine.motors.mmPerRev=130.0
controller.vector.filename=C\:\\Users\\Ryan\\Desktop\\svg's\\shapes.svg
controller.window.width=1350
controller.frame.colour=C80000
controller.image.position.y=202
controller.image.position.x=103
machine.motors.accel=400
controller.image.height=543
controller.machine.serialport=0
controller.window.height=678
controller.maxSegmentLength=2
machine.penlift.up=92
machine.penlift.down=44
controller.page.position.y=120
controller.vector.scaling=84.1
controller.page.position.x=51
controller.pictureframe.width=239
machine.step.multiplier=4
controller.grid.size=25.0
controller.testPenWidth.endSize=2
controller.pictureframe.height=236
controller.page.colour=DCDCDC
controller.testPenWidth.incrementSize=0.51
controller.image.width=831
machine.motors.stepsPerRev=200.0
machine.pen.size=0.42
controller.page.width=502
controller.pixel.mask.color=00FF00
controller.machine.baudrate=57600
controller.vector.minLineLength=0
machine.width=605
controller.page.height=379
controller.vector.position.y=68.68
controller.background.colour=646464
controller.image.filename=
controller.vector.position.x=42.99
controller.homepoint.y=120
controller.guide.colour=FFFFFF
machine.motors.maxSpeed=600
controller.homepoint.x=302
controller.density.preview.style=2
controller.pixel.scaling=1
controller.densitypreview.colour=000000
machine.height=590

Image
Image
Image
sandy
Administrator
Posts: 1317
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sandy
Post Re: Also having troubles with straight lines
on: December 29, 2014, 21:03
Quote

Hello, you didn't mention what kind of driver hardware you have, but I guess it is an adafruit motorshield.

Settings for motorshield v1 is
stepsPerRev = actual motor steps * 2 = 400
stepMultiplier = 1

There might be some distortion in the photograph, but if the distance from the dot on the centreline to the home point is 120mm, then I measure the width to be 634mm. The distance from the inside edge of the sprocket, to the inside edge of the opposite sprocket.

The screenshot shows machine width being 780mm, but the default.properties.txt says 600.

Assuming your sprocket circumference really is 130mm, I can't really see anything else (other than the stepsPerRev=200 and stepMultiplier=4) that would be wrong. That said, those figures are definitely wrong.

Change settings one at a time, remember to upload machine spec.

sn
RyanSchuij-
er
Newbie
Posts: 2
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RyanS
Post Re: Also having troubles with straight lines
on: January 3, 2015, 12:43
Quote

Thank you for your help! Your given numbers did the trick.

Image
sandy
Administrator
Posts: 1317
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sandy
Post Re: Also having troubles with straight lines
on: January 3, 2015, 14:07
Quote

Square and true! Good work.
maykosalom-
ao
Newbie
Posts: 5
Permalink
Post Re: Also having troubles with straight lines
on: March 19, 2017, 00:21
Quote

Hello!!!
I am having the same problem but unfortunately I do not use the same equipment!
My equipments are:
Nema Engine 23
(http://motion.schneider-electric.com/downloads/quickreference/NEMA23.pdf)
Drive DIV268N-5A
(http://www.thanksbuyer.com/download/TB6600.pdf)
Obs1: I'm using microstep 1/4
Obs2: The circumference of the sprocket is 6.35mm because it is the motor shaft itself.

SETUP POLARGRAPH
123 MM PER REV
200 STEP PER REV
5 STEP MULTIPLIER
sandy
Administrator
Posts: 1317
Permalink
sandy
Post Re: Also having troubles with straight lines
on: March 19, 2017, 09:09
Quote

Steps per revolution is probably 200 (though i cant see anything in the data sheet that actually says that).
MM per revolution should be 6.35 * pi ( the circumference of the "sprocket").
Step multiplier should be 4 if your drivers are using quarter steps.

If all those things are right, then check your machine size and home position.
maykosalom-
ao
Newbie
Posts: 5
Permalink
Post Re: Also having troubles with straight lines
on: March 19, 2017, 21:51
Quote

Hello!!!
I made the modifications but the drawings are still trotting and are not of the specified size.
What should you do ???
Some results:
https://mega.nz/#!9EFlDY5J!lwT6WhOPiVk6ICAulbXwfj7EYsuqIH5RLwcINK0ZS0E
https://mega.nz/#!4J10FJpS!_NXQeKaee7ovHBmXOvUhHCOvV1rNYa4ICW5oGvAC1XM

default.properties:
# *** Polargraph properties file ***
#Sun Mar 19 18:13:44 BRT 2017
controller.pixel.samplearea=10
controller.pictureframe.position.y=200
controller.pictureframe.position.x=211
controller.testPenWidth.startSize=0.7
controller.machine.colour=969696
machine.motors.mmPerRev=45.5
controller.window.width=1366
controller.frame.colour=C80000
controller.image.position.y=122
controller.image.position.x=98
machine.motors.accel=700
controller.image.height=392
controller.machine.serialport=0
controller.window.height=706
controller.maxSegmentLength=2
controller.geomerative.polygonizerLength=15.9
machine.penlift.up=0
machine.penlift.down=90
controller.page.position.y=186
controller.vector.scaling=30.6
controller.page.position.x=198
controller.pictureframe.width=392
machine.step.multiplier=4
controller.grid.size=12.0
controller.testPenWidth.endSize=1
controller.pictureframe.height=571
controller.page.colour=DCDCDC
controller.testPenWidth.incrementSize=0.2
controller.image.width=392
machine.motors.stepsPerRev=200.0
machine.pen.size=0.7
controller.page.width=420
controller.pixel.mask.color=86875F
controller.machine.baudrate=57600
controller.vector.minLineLength=0
machine.width=816
controller.geomerative.polygonizer=0
controller.page.height=596
controller.vector.position.y=197.88
controller.background.colour=646464
controller.image.filename=
controller.vector.position.x=184.95
controller.homepoint.y=186
controller.guide.colour=FFFFFF
machine.motors.maxSpeed=600
controller.homepoint.x=408
controller.density.preview.style=6
controller.pixel.scaling=1.34
controller.densitypreview.colour=000000
machine.height=900
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