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Topics - ggallant571

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Projects / Simple f18 etch
« on: January 21, 2019, 10:07:15 AM »
Attached is a simple etchable F18 image. Sized for 100x100mm slate at 254dpi resolution

General Discussion / Artwork cleanup
« on: December 30, 2018, 02:08:16 PM »
I do mostly raster burning of images downloaded (pinterest) and scanned photos. I prefer narrow lines (one or two pixels wide) and often spend 20 hours getting an image clean. My primary tool is GIMP on Linux. Sometimes I have tried center line trace tools in inkscape, potrace,  and from online sites. Nothing really worked well. I would like the overall image outline to be really good. Most of the utilities gave too much rounding, large gaps, and strange lines.

Last week I wrote a couple of image cleanup programs that try to do a center line detection geared towards lmy workflow. Ideal goal is a single pixel wide PNG image with easy to add/erase pixels. Both are far from perfect but the later of the two looks promising. I am interested in getting some other images to test. If you have any raster image files (in both raw and touched up form) I would appreciate getting a few. Contact me via email and I will reply with the utility generated touched up image and comments about any manual rework.

General algorithm:
    1. Get PNG file info, allocate memory, and read file.
    2. Reduce image to black/white
    3. Remove random speckles
    4. Preform simple edge smoothing.
    5. Mark any single wide/tall pixels as DONE.
    6. Find the outline of all embedded shapes.
    7. Selectively mark pixels next to outline as DONE
    8. Selectively mark the pixels as white
    9. Remove odd tabs and other cleanup
   10. Repeat steps 5 thru 9
   11. Write PNG output file.

It sure is nice to have fast PC with lots of memory. Program is command line Linux. Will attempt to make a Windows version once things stabilize.

General Discussion / Possible HOME problem withe grbl 1.1f
« on: December 17, 2018, 07:34:25 AM »
I have a core-xy fixture that has X & Y axis HOME switches. Getting strange behavior on the first homing cycle after a power-on. It properly performs the switch detect operation. If I then move to (0,0) it moves to the far corner and hits the rails.

I expect the firmware reset the virtual (0,0) on completion of the HOME cycle.

General Discussion / Picture frames
« on: December 16, 2018, 06:07:37 PM »
I have been looking for 4x4 inch (10.2x10.2 cm) picture frames for a couple of years. Stumbled upon some at Walmart for $0.94US and bought a couple. They are truly simple plastic frames that happen to nicely hold 1/16 inch (1.5mm) thick basswood etchings. BTW -3/32 is too thick. I've done 8 seasonal etchings that have all found new homes after a brief stint on a window sill.

I think the part number is MS98-210-274-61. Online has packs of 6 with a slightly different look for $5.99US.

General Discussion / ESP32
« on: December 05, 2018, 04:50:26 AM »
There is an active project to support grbl on ESP32. It is hosted on github which I have been monitoring for about 3 months. Sounds like it is pretty stable. Ready to give it a try. Does require a new controller board and there are at least 10 flavors of ESP32 boards out there with little documentation and zero consistency in pin mappings (I have 4). 

General Discussion / Center Trace
« on: November 28, 2018, 10:09:29 PM »
I am looking for a utility or algorithm to do center trace. I have been manually pixel editing images to get them single pixel wide Then fatten the trace as necessary depending on the material and laser. Basswood with a 1.6W laser burns really nice with 2 pixel (0.2mm) trace whereas the same image in slate looks better with 0.4mm burn path.

General Discussion / New source for slate
« on: November 26, 2018, 02:04:15 PM »
Went to Michaels today for some 3mm basswood and slate. They were out of slate and the clerk indicated there is none on order. Having purchased between 75 and 100 packs of 4 in the past year I asked why and they indicated they were no longer carrying slate coasters. The quality has deteriorated over the past year with about 10% being unusable. Need a new source or a change in etching material. BTW - I am in a craft store deprived corner of the world.

General Discussion / Etching bamboo wood
« on: November 23, 2018, 09:56:53 AM »
I am about to etch a double level bamboo lazy susan. Top layer has 1 large image while bottom layer has 4 smaller. It is not a very expensive part but it would be nice to get the settings correct on the first try.

Laser is a generic 3-wire 2.5W on a core-zy fixture. I suspect the actual speed is off by the square root of two but will do some experiments on scrap wood first.

General Discussion / Displaying recent posts
« on: November 01, 2018, 01:04:50 PM »
Is there a method to display the last N posts across all topics?

General Discussion / Homing switches
« on: October 24, 2018, 08:15:29 AM »
I have been using homing switches for a couple of years now and have an idea to improve the precision.

  1. Wire a CPU control line to the micro stepping mode pins on the controller
  2. Jog the machine using mode 16 till the switch closes.
  3. Back off till switch opens.
  4. Switch to stepping mode 1 and back off 2 complete steps.
  5. Resume stepping mode 16.

My thought is let the magnets in the motor force the alignment to increments of 1.8 degrees.

Not being a stepper motor or controller guru this is just an idea. Perhaps resetting the controller would do the same. Comments welcome!!!

Projects / Seasonal etching
« on: October 12, 2018, 09:37:26 PM »
Seasonal image for those of you in Northern climates. Etched nicely in wood with 1.6W laser with nice sharp focus. 0.1 resolution, 900mm/pin, full power. Original came from pinterest adult coloring book pages.

Custom Size Frames / Core-XY firmware for Arduino Nano
« on: October 04, 2018, 08:18:00 AM »
I am in the finishing stages of building a core-xy etcher and ran into a firmware problem. Built the grbl-1.f firmware from scratch and configured for CORE_Xy. Loads and runs on an Arduino UNO. Corrupts the bootloader on the Nano (tried 3 Nanos). I suspect the image is slightly too large. Does the update once and fails the verification pass, Unit is useless after,

Used an Arduino  UNO to install a new bootloader and can repeat the process. Changed the target machine from Nano to UNO and reloaded the bootloader. Now it accepts and run the grbl firmware.

General Discussion / 15 watt laser
« on: September 17, 2018, 08:31:03 AM »
I have purchased the components to build a 15W laser with linear slides. Two questions / concerns:

1. What do they mean by 50% duty cycle? Max PWM of 50% or run for 5 minutes and off for 5 minutes?
2. I am wondering if the HOME switch movement should be with no micro stepping to avoid the motor starting at a full step position.

Projects / World Map
« on: September 06, 2018, 05:45:31 PM »
I was away from home for a few days and came dome with LSAS - Laser Separation Anxiety Syndrome. Attached is a PNG map of the world along with an etching on scrap wood. I apologize in advance if I incorrectly adjusted the outline of your corner of the world. I was trying to get lines 3 pixels wide with 3 pixel separation. Feel free to make corrections and post better results.

Engraving / Stepper motor problem
« on: September 04, 2018, 04:46:42 PM »
I am having a strange stepper motor problem. The etcher has a single motor on the X axis and 2 motors on the Y. X is working fine, Either of the Y's by themselves is OK. Both Y's and they seem to be fighting each other. Lots of jitter and noise. Almost as if one motor was being driven as a generator. Swapped cables and driver boards. This fixture had been working very smoothly. I think all three motors are identical.

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