0.9 degree Stepper

[Ralf Hesterberg]

Hi

 

I have some 0.9 degree steppers here. Does the eggbot support these?

 

Thanks

Ralf

[Windell H. Oskay]

On Mar 24, 2012, at 7:32 AM, Ralf Hesterberg wrote:

> Hi
> I have some 0.9 degree steppers here. Does the eggbot support these?

It does not by default, but it should be relatively straightforward for you to add it. This is assuming, of course, that the motors are of similar current/voltage characteristics and can be driven by the EBB.

Some background:
The Eggbot kit uses 200 step per revolution motors (360 degrees/200 steps = 1.8 degree/step), and has 16X microstepping drivers, to give a total of 3200 steps per revolution in each motor.

An older version of the kit used 400 step per revolution motors (360 degrees/400 steps = 0.9 degree/step), and had 8X microstepping drivers, to give a total of 3200 steps per revolution.

During our beta testing, one of our team ended up with the 200 step/rev motors and 8X microstepping drivers, which gave 1600 steps per revolution, so we built a facility into the software that could work successfully with 1600 steps per revolution. We should be able to adapt this ability to work with other resolution changes as well.

Now, I presume that your goal is to *increase* the resolution by a factor of two, to give 6400 steps per revolution, rather than to "scale down" the motor to still give 3200 steps per revolution. (If you want the latter, that can be done as well-- but it's a slightly different process.)

To make the modification:

1. First, locate the file "eggbot.py" within your Inkscape Extensions folder.

- On Windows, this directory is (your Program Files directory)\Inkscape\share\extensions
- On Mac, this directory is /Applications/Inkscape.app/Contents/Resources/extensions
(To get there, you can use the Finder, under menu item Go> Go to Folder... )

2. Open up the file "eggbot.py" with a text editor. This is a python file, so be *very* careful not to add or delete any extra returns, spaces, or other invisible characters-- python is unforgiving of such things.

3. (Modification 1 of 2): Search for "import motor1600" and change that text to "import motor6400".

4. (Modification 2 of 2): On the following line, which reads "self.step_scaling_factor = 2", change that to say "self.step_scaling_factor = 0.5"

5. Save the file.

6. Make a new *empty* plain-text file in the extensions directory, called "motor6400.py"
If this file is present, the Eggbot should operate normally, but with 6400 steps per revolution. To go back to normal (3200 step/rev) operation, remove or rename the file.

I have not tested this, so please let me know if it works or does not work as expected.

[Ralf Hesterberg]

Hi

Thanks. It works, but with some problems. After every "line" the program stops and you must resume manually. The same svg with the standard resolution works without interrupts.

Does the resolution increase with this workaround? Or is it the better way to scale all svg to 6400px?

Thanks
Ralf
________________________________________
Von: eggbo...@googlegroups.com [eggbo...@googlegroups.com]" im Auftrag von "Windell H. Oskay [win...@oskay.net]
Gesendet: Samstag, 24. März 2012 22:55
An: eggbo...@googlegroups.com
Betreff: Re: [EggBot] 0.9 degree Stepper

To make the modification:

5. Save the file.

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[Windell H. Oskay]

On Apr 2, 2012, at 12:46 AM, Ralf Hesterberg wrote:

> Thanks. It works, but with some problems. After every "line" the program stops and you must resume manually. The same svg with the standard resolution works without interrupts.
>
> Does the resolution increase with this workaround? Or is it the better way to scale all svg to 6400px?

Hmm.
Would you please revert the program to its original version, and try operating it with a file present named "motor1600.py" ? I'm curious as to whether there was some kind of a bug introduced by your modification (either your fault or mine), or whether the bug was already present in the low-res version.

If this does work, it's the best method, because the software is aware of the number of pixels that are needed to wrap around (3200, normally) and can use that information while taking shortcuts to move to the nearest point.

-Windell

[Ralf Hesterberg]

The problem is the self.step_scaling_factor = 0.5 with 2 it will work also with 1.

-----Ursprüngliche Nachricht-----
Von: eggbo...@googlegroups.com [mailto:eggbo...@googlegroups.com] Im Auftrag von Windell H. Oskay
Gesendet: Montag, 2. April 2012 19:07

An: eggbo...@googlegroups.com
Betreff: Re: [EggBot] 0.9 degree Stepper

-Windell

--

[Windell H. Oskay]

> The problem is the self.step_scaling_factor = 0.5 with 2 it will work also
> with 1.

Thank you; I'll see if I can figure out where the issue is.

[Windell H. Oskay]

On Apr 2, 2012, at 1:54 PM, Ralf Hesterberg wrote:

> The problem is the self.step_scaling_factor = 0.5 with 2 it will work also with 1.

Hi Ralf,
I've posted this issue as an enhancement request on our google code site, with a possible fix for you:
http://code.google.com/p/eggbotcode/issues/detail?id=52

Cheers,
-Windell

[Ralf Hesterberg]

Hi Windell,

Thanks. This seem to be working...

Ralf

-----Ursprüngliche Nachricht-----
Von: eggbo...@googlegroups.com [mailto:eggbo...@googlegroups.com] Im Auftrag von Windell H. Oskay

Gesendet: Freitag, 6. April 2012 05:19

An: eggbo...@googlegroups.com
Betreff: Re: [EggBot] 0.9 degree Stepper

Cheers,
-Windell

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