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Modification of 12 pointed star for 12mm diffused thin digital RGB LED pixels

by scanner Dec 19, 2014
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Thank you for putting this up. Looking forward to trying it, but I am having trouble understanding the files to print. I started with ChristmasStarPiece_thin_v4.stl, but there is no hole for the LED. Is that file there just to add in different size bullet pixels?

ChristmasStarPiece_thin_v4.stl is the unmodified base piece from another design. The designs with the holes for mounting the LED's are star_point_bottom.stl and star_point.stl

Thanks for the info. I figured that had to be the case, but wanted to make sure.

Great remix, thank you for sharing.
I would like to scale this up, maybe around 150% which works great, except for the LED hole.
What I would like to do is be able to adjust the diameter of the LED hole, and maybe the height too, if possible.
I have tried many changes to the scad file, but since I have almost no skills in that area, I would appreciate any help you could offer.
Of course, I could simply remove the LED 'tube' but I would prefer to keep it as original as possible to your design.
The LEDs I have are 12mm (ish) WS2812 string that I plan to control with an Arduino Nano.

To scale it up you will need to go in to the OpenSCAD file and re-scale the imported ChristmasStarPiece_thin_v4.stl file inside OpenSCAD. To fit your LED you wil need directly modify the code in the file under the function 'bullet_pixel' which is the shape of the LED fixture you want to use to fit your LED.

So by re-scaling the STL you do not change the scale of the fixture for the LED.

First of all, thank you so much for your fast reply.
I have been tinkering with the scale, after looking online, but I'm clearly not getting it. So far I have the following, but still it's not right;
module star() {
difference() {
rotate([0,0,18])translate([-24,-24,10]) {
scale([1.7,1.7,1.7])import(file="ChristmasStarPiece_thin_v4.stl",layer="",convexity=15);
}
bullet_pixel();
}
}

Also, would you mind explaining what the variables within the "bullet_pixel" do.

Thank you

bullet_pixel:

bullet_r - the radius of the main body of the LED
bullet_led_r - the radius of the top of the body where the LED is
bullet_h - the height of the main body of the LED
bullet_top_h - the height of the top of the body where the LED is.

To get a better idea this is the actual "bullet LED" : https://www.adafruit.com/product/322

So the hole is made for this LED to fit snuggly inside of it.

As for the scaling of the star that looks right but I would fix the code a bit by putting braces ('{' and '}') around the rotate sub-clause, so:

difference() {
      rotate( .... ) {
          translate( ... ) {
                  scale( ... ) {
                      import(....);
                  }
          }
      }
     bullet_pixel();
}

Thank you,

So far it looks like this;
module star() {
difference() {
rotate( [0,0,18] ) {
translate( [-24,-24,10] ) {
scale( [1.7,1.7,1.7] ) {
import(file="ChristmasStarPiece_thin_v4.stl",layer="",convexity=15);
}
}
}
bullet_pixel();
}
}

But with the scale set to 1.7, the whole arm moves off-centre thus it is not aligned with the bullet or the gripper cutouts.
Can you explain how to compensate please?

I am very sorry for being such a nuisance, but I am trying to get to grips with this as I go.

I would start with just making a scaled up star stl...

First start with just trying to scale up the star:

scale( .... ) {
   import( .... );
}

once that is looking right in OpenSCAD then work with 'rotate()' and 'translate()' to have the star centered at 0,0,0:

rotate( ... ) {
    translate( .... ) {
        scale( ... ) {
           import( .. );
        }
     }
}

it might be easier to fiddle with rotate() until the star is pointing in the right direction. Once you have the star "pointing perfectly up" then work with translate to move it to 0,0,0. Once you have that, then work on getting the bullet_pixe() cutout from the star's base.

What did you print yours in? I tried a single spike in ABS white, which is OK for 2 layer LED/Pixel covers, but way too dull for this. Natural ABS is heading via post this week, but I don't think that will help a lot, so I think a clear might be best.

The first one I did in clear PLA. But all of the ones after that, since I have a Replicator 2X and that can not print PLA (stupid design problem from MakerBot), I use a clear ABS instead.

Natural ABS will work better than White ABS.. but really your best bet is with something clear. Either natural PLA or something like: http://www.amazon.com/Zen-Toolworks-Printer-Translucent-Filament/dp/B009LDWST8/ref=sr_1_1?ie=UTF8&qid=1434980676&sr=8-1&keywords=clear+abs+filament