The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

The New Hotness

  • Glass Tiles: Matrix for SK6812 PCBs

    Tweaking the glass tile frame for press-fit SK6812 PCBs in the bottom of the array cells:

    Glass Tile Frame - cell array - openscad
    Glass Tile Frame – cell array – openscad

    Which looks like this with the LEDs and brass inserts installed:

    Glass Tile - 2x2 array - interior
    Glass Tile – 2×2 array – interior

    The base holds an Arduino Nano with room for wiring under the cell array:

    Glass Tile Frame - base - openscad
    Glass Tile Frame – base – openscad

    Which looks like this after it’s all wired up:

    Glass Tile - 2x2 array - wiring
    Glass Tile – 2×2 array – wiring

    The weird colors showing through the inserts are from the LEDs. The red thing in the upper left is a silicone insulation snippet. Yes, that’s hot-melt glue holding the Arduino Nano in place and preventing the PCBs from getting frisky.

    Soak a handful of glass tiles overnight in paint stripper:

    Glass Tiles - paint stripper soak
    Glass Tiles – paint stripper soak

    Whereupon the adhesive slides right off with the gentle application of a razor scraper. Rinse carefully, dry thoroughly, and snap into place.

    Tighten the four M3 SHCS and it’s all good:

    Glass Tile - 2x2 array - operating
    Glass Tile – 2×2 array – operating

    So far, I’ve had two people tell me they don’t know what it is, but they want one:

    Glass Tile - various versions
    Glass Tile – various versions

    The OpenSCAD Customizer lets you set the array size:

    Glass Tile Frame - 3x3 - press-fit SK6812 LEDs
    Glass Tile Frame – 3×3 – press-fit SK6812 LEDs

    However, just because you can do something doesn’t mean you should:

    Glass Tile Frame - 6x6 cell array - openscad
    Glass Tile Frame – 6×6 cell array – openscad

    Something like this might be interesting:

    Glass Tile Frame - 2x6 cell array - openscad
    Glass Tile Frame – 2×6 cell array – openscad

    In round numbers, printing the frame takes about an hour per cell, so a 2×2 array takes three hours and 3×3 array runs around seven hours. A 6×6 frame is just not happening.

    The OpenSCAD source code as a GitHub Gist:

    // Illuminated Tile Grid
    // Ed Nisley – KE4ZNU
    // 2020-05
    /* [Configuration] */
    Layout = "Build"; // [Cell,CellArray,MCU,Base,Show,Build]
    Shape = "Square"; // [Square, Pyramid, Cone]
    Cells = [2,2];
    CellDepth = 15.0;
    Inserts = true;
    SupportInserts = true;
    /* [Hidden] */
    ThreadThick = 0.25;
    ThreadWidth = 0.40;
    HoleWindage = 0.2;
    function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);
    Protrusion = 0.1; // make holes end cleanly
    ID = 0;
    OD = 1;
    LENGTH = 2;
    Tile = [25.0 + 0.1,25.0 + 0.1,4.0];
    WallThick = 4*ThreadWidth;
    FloorThick = 3.0;
    Flange = [2*ThreadWidth,2*ThreadWidth,0]; // ridge supporting tile
    Separator = [3*ThreadWidth,3*ThreadWidth,Tile.z – 1]; // between tiles
    Screw = [3.0,6.0,3.5]; // M3 SHCS, OD=head, LENGTH=head
    Insert = [3.0,4.2,8.0]; // threaded brass insert
    ScrewRecess = Screw[LENGTH] + 4*ThreadThick;
    LEDPCB = [9.6,9.6,2.9]; // round SK6812, squared-off sides
    LED = [5.0 + 2*HoleWindage,5.0 + 2*HoleWindage,1.3];
    LEDOffset = [0.0,0.0,0.0]; // if offset from PCB center
    CellOAL = [Tile.x,Tile.y,0] + Separator + [0,0,CellDepth] + [0,0,FloorThick];
    ArrayOAL = [Cells.x*CellOAL.x,Cells.y*CellOAL.y,CellOAL.z]; // just the LED cells
    BlockOAL = ArrayOAL + [2*WallThick,2*WallThick,0]; // LED cells + exterior wall
    echo(str("Block OAL: ",BlockOAL));
    InsertOC = ArrayOAL – [Insert[OD],Insert[OD],0] – [WallThick,WallThick,0];
    echo(str("Insert OC: ",InsertOC));
    TapeThick = 1.0;
    Arduino = [44.0,18.0,8.0 + TapeThick]; // Arduino Nano to top of USB Mini-B plug
    USBPlug = [15.0,11.0,9.0]; // USB Mini-B plug insulator
    USBOffset = [0,0,5.0]; // offset from PCB base
    WiringSpace = 3.5;
    WiringBay = [(Cells.x – 1)*CellOAL.x + LEDPCB.x,(Cells.y – 1)*CellOAL.y + LEDPCB.x,WiringSpace];
    PlateOAL = [BlockOAL.x,BlockOAL.y,FloorThick + Arduino.z + WiringSpace]; // allow wiring above Arduino
    echo(str("Base Plate: ",PlateOAL));
    echo(str("Screw length: ",(PlateOAL.z – ScrewRecess) + Insert.z/2," to ",(PlateOAL.z – ScrewRecess) + Insert.z));
    LegendRecess = 1*ThreadThick;
    //————————
    module PolyCyl(Dia,Height,ForceSides=0) { // based on nophead's polyholes
    Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2);
    FixDia = Dia / cos(180/Sides);
    cylinder(d=(FixDia + HoleWindage),h=Height,$fn=Sides);
    }
    //———————–
    // Base and optics in single tile
    module LEDCone() {
    hull() {
    translate([0,0,CellDepth + Tile.z/2])
    cube(Tile – 2*[Flange.x,Flange.y,0],center=true);
    if (Shape == "Square") {
    translate([0,0,LEDPCB.z/2])
    cube([Tile.x,Tile.y,LEDPCB.z] – 2*[Flange.x,Flange.y,0],center=true);
    }
    else if (Shape == "Pyramid") {
    translate([0,0,LEDPCB.z/2])
    cube(LEDPCB,center=true);
    }
    else if (Shape == "Cone") {
    translate([0,0,LEDPCB.z/2])
    cylinder(d=1.0*LEDPCB.x,h=LED.z,center=true);
    }
    else {
    echo(str("Whoopsie! Invalid Shape: ",Shape));
    cube(5);
    }
    }
    }
    // One complete LED cell
    module LEDCell() {
    difference() {
    translate([0,0,CellOAL.z/2])
    cube(CellOAL + [Protrusion,Protrusion,0],center=true); // force overlapping adjacent sides!
    translate([0,0,CellOAL.z – Separator.z + Tile.z/2])
    cube(Tile,center=true);
    translate([0,0,LEDPCB.z])
    LEDCone();
    // cube([LED.x,LED.y,CellOAL.z],center=true);
    translate(-LEDOffset + [0,0,-CellOAL.z/2])
    rotate(180/8)
    PolyCyl(LEDPCB.x,CellOAL.z,8);
    }
    }
    // The whole array of cells
    module CellArray() {
    difference() {
    union() {
    translate([CellOAL.x/2 – Cells.x*CellOAL.x/2,CellOAL.y/2 – Cells.y*CellOAL.y/2,0])
    for (i=[0:Cells.x – 1], j=[0:Cells.y – 1])
    translate([i*CellOAL.x,j*CellOAL.y,0])
    LEDCell();
    if (Inserts) // bosses
    for (i=[-1,1], j=[-1,1])
    translate([i*InsertOC.x/2,j*InsertOC.y/2,0])
    rotate(180/8)
    cylinder(d=Insert[OD] + 2*WallThick,h=Insert[LENGTH],$fn=8);
    }
    if (Inserts) // holes
    for (i=[-1,1], j=[-1,1])
    translate([i*InsertOC.x/2,j*InsertOC.y/2,-Protrusion])
    rotate(180/8)
    PolyCyl(Insert[OD],Insert[LENGTH] + FloorThick + Protrusion,8);
    }
    difference() {
    translate([0,0,CellOAL.z/2])
    cube(BlockOAL,center=true);
    translate([0,0,CellOAL.z])
    cube(ArrayOAL + [0,0,2*CellOAL.z],center=true);
    }
    }
    // Arduino bounding box
    // Origin at center bottom of PCB
    module Controller() {
    union() {
    translate([0,0,Arduino.z/2])
    cube(Arduino,center=true);
    translate([Arduino.x/2 – Protrusion,-USBPlug.y/2,USBOffset.z + TapeThick – USBPlug.z/2])
    cube(USBPlug + [Protrusion,0,0],center=false);
    }
    }
    // Baseplate
    module BasePlate() {
    difference() {
    translate([0,0,PlateOAL.z/2])
    cube(PlateOAL,center=true);
    translate([PlateOAL.x/2 – Arduino.x/2 – 2*WallThick,0,FloorThick])
    Controller();
    translate([PlateOAL.x/2 – Arduino.x/2 – 2*WallThick,0,FloorThick + PlateOAL.z/2])
    cube([Arduino.x – 2*2.0,WiringBay.y,PlateOAL.z],center=true); // cutouts beside MCU
    translate([0,0,PlateOAL.z – WiringBay.z + PlateOAL.z/2 – Protrusion])
    cube([PlateOAL.x – 2*WallThick,WiringBay.y,PlateOAL.z],center=true); // cutout above MCU
    translate([0,0,PlateOAL.z – WiringBay.z + PlateOAL.z/2 – Protrusion])
    cube([WiringBay.x,PlateOAL.y – 2*WallThick,PlateOAL.z],center=true); // cutout above MCU
    if (Inserts)
    for (i=[-1,1], j=[-1,1])
    translate([i*InsertOC.x/2,j*InsertOC.y/2,-Protrusion])
    rotate(180/8) {
    PolyCyl(Screw[ID],2*PlateOAL.z,8);
    PolyCyl(Screw[OD],ScrewRecess + Protrusion,8);
    }
    cube([45,17.0,2*LegendRecess],center=true);
    }
    linear_extrude(height=2*LegendRecess) {
    translate([0,1])
    rotate(-0*90) mirror([1,0,0])
    text(text="Ed Nisley",size=6,font="Arial:style:Bold",halign="center");
    translate([0,-6.5])
    rotate(-0*90) mirror([1,0,0])
    text(text="softsolder.com",size=4.5,font="Arial:style:Bold",halign="center");
    }
    Fin = [Screw[OD]/2 – 1.5*ThreadWidth,2*ThreadWidth,ScrewRecess – ThreadThick];
    if (Inserts && SupportInserts)
    color("Yellow")
    for (i=[-1,1], j=[-1,1])
    translate([i*InsertOC.x/2,j*InsertOC.y/2,0]) {
    rotate(180/8)
    cylinder(d=6*ThreadWidth,h=ThreadThick,$fn=8);
    for (a=[0:90:360])
    rotate(a)
    translate([Fin.x/2 + ThreadWidth/2,0,(ScrewRecess – ThreadThick)/2])
    cube(Fin,center=true);
    }
    }
    //———————–
    // Build things
    if (Layout == "Cell")
    LEDCell();
    else if (Layout == "CellArray")
    CellArray();
    else if (Layout == "MCU")
    Controller();
    else if (Layout == "Base")
    BasePlate();
    else if (Layout == "Show") {
    translate([0,0,3*PlateOAL.z])
    CellArray();
    BasePlate();
    translate([PlateOAL.x/2 – Arduino.x/2 – 2*WallThick,0,FloorThick])
    color("Orange",0.3)
    Controller();
    }
    else if (Layout == "Build") union() {
    translate([0,0.6*BlockOAL.y,0])
    CellArray();
    translate([0,-0.6*BlockOAL.x,0])
    rotate(90)
    BasePlate();
    }