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• mistakes been made

  davedarko • 12/30/2021 at 11:38 • 0 comments

  I missed that one LED wasn't correctly placed in the schematics and one connection is missing. Have to go in with magnet wire and fix that on all 15 boards :)

• shapes

  davedarko • 12/17/2021 at 19:33 • 0 comments

  Always tough googling something when you're looking for the name to google in the first place. I needed the "dihedral angle" of a dodecahedron, meaning the angle between the sides / faces of the body. It's 116.56505°. The cool thing is, with that Angle I can basically nibble away all sides and have the perfect folding angle for this! But for now I just eye-balled it.

  // 
  
  difference()
  {
      cylinder(3, 35, 33.15, $fn=5);
      union() {
          color("red") cylinder(1, 30 , 30, $fn=5);
          color("red")translate([0,0,1]) cylinder(2, 32 , 31, $fn=5);
      }
  }
  
  translate([-31, -25, 6]) rotate([ 0, 116.56505, 0]) cube([5,50,5]);

• First boards are ordered after 2 years

  davedarko • 12/15/2021 at 17:02 • 0 comments

  Since I'm visiting family in America, I found some time to tackle those weird PCB designs that I always talk about, but never do. Two years ago I made the #Do or Donut SAO  , which rhymes with this project as in me using the same(?) chip to control a bunch of LEDs. When I started this, two things came clear: I did not want to use more than one chip on a board and that basically meant going for 51 LEDs. You can read up on all my minor design choices and routing issues on twitter: https://twitter.com/davedarko/status/1468990742316167171

  The distance between the LEDs in not the same at all, as the five triangles that make up the pentagon have angles of 72-54-54 degrees and are there for not symmetrical in all the directions. But I'm happy with the spacing, so I proceeded.

  I should be able to power everything with a considerate brightness from a smaller battery, as was the LED cubes I took inspiration from. Heat should not be a problem either, but we'll see about that. The dodecahedron will have a height about 5cm.

  The chip can have up to 16 addresses, so that's perfect for controlling the 12 boards with one IC. I have not calculated the frame rates of anything, the chips talk I2C with up to 1MHz, to up to 12x16 LEDs. 

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