/* Project box

A parametric box for electronics projects using perforated circuit boards. The
board is held above the bottom of the box by four corner supports, and snaps
into place to hold it snugly while allowing easy removal.
*/

$fn=50;

board_x = 50;
board_y = 70;
board_thickness = 1;   // [1:10]
clearance_above = 20;  // [5:50]
clearance_below = 10;  // [5:50]
fit_tolerance = 0.5;
corner_radius=3;       // [1:10]
support_radius=5;      // [1:10]
wall_width=3;          // [3:10]

module _rounded_box(h, w, d, r) {
  hull() {
    translate([0 + r,0 + r,0])
      cylinder(h=h,r=r);
    translate([w - r,0 + r,0])
      cylinder(h=h, r=r);
    translate([w - r,d - r,0])
      cylinder(h=h, r=r);
    translate([0 + r,d - r,0])
      cylinder(h=h, r=r);
  }

}

module corner_post(h, r) {
  intersection() {
    translate([-0.001,-0.001,-0.001])
      cube([r*1.1, r*1.1, h*1.2]);
    cylinder(h=h, r=r);
  }
}

module lid_base(x, y, z, slot_depth=1.5) {
  polyhedron([// bottom face
              [0, 0, 0],
              [x, 0, 0],
              [x, y, 0],
              [0, y, 0],
              // top face
              [slot_depth, 0, z],
              [x - slot_depth, 0, z],
              [x - slot_depth, y, z],
              [slot_depth, y, z]],
             [[0,1,2,3],
              [4,5,1,0],
              [7,6,5,4],
              [5,6,2,1],
              [6,7,3,2],
              [7,4,0,3]]);
}

module project_box(x, y,
                   above=20,
                   below=10,
                   board_thickness=1,
                   fit_tolerance=0.5,
                   corner_radius=3,
                   support_radius=5,
                   wall_width=3) {
  width=board_x + (fit_tolerance * 2);
  depth=board_y + (fit_tolerance * 2);
  lid_width = width + wall_width; // Extends halfway into each side wall
  lid_depth = depth + wall_width; // Extends out of one wall
  lid_height = wall_width;        // Replaces most of the top wall
  height=board_thickness + above + below + (fit_tolerance * 2) + lid_height;

  // container
  difference() {
    _rounded_box(h=height + (wall_width * 2),
                 w=width + (wall_width * 2),
                 d=depth + (wall_width * 2),
                 r=corner_radius);
    translate([wall_width,wall_width,wall_width])
      cube([width, depth, height + (wall_width * 2)]);
    // lid slot
    translate([wall_width / 2, wall_width, height + wall_width + 0.001]) {
      lid_base(lid_width, lid_depth, lid_height);
    }
  }

  // supports
  translate([wall_width,wall_width,wall_width]) {
    translate([0,0,0])
      corner_post(h=below, r=support_radius);
    translate([width,0,0])
      rotate([0,0,90])
      corner_post(h=below, r=support_radius);
    translate([0,depth,0])
      rotate([0,0,270])
      corner_post(h=below, r=support_radius);
    translate([width,depth,0])
      rotate([0,0,180])
      corner_post(h=below, r=support_radius);
  }


  // locking nubs
  translate([wall_width,wall_width,wall_width]) {
    nub_size = 1;
    nub_width = board_y / 4;
    nub_height = below + board_thickness + (nub_size/2) + (fit_tolerance*2);
    translate([0,board_y / 2 - nub_width / 2,nub_height])
      rotate([270,0,0])
      cylinder(h=nub_width, r=nub_size/2);
    translate([width,board_y / 2 - nub_width / 2,nub_height])
      rotate([270,0,0])
      cylinder(h=nub_width, r=nub_size/2);
  }
}

project_box(board_x, board_y,
            above=clearance_above,
            below=clearance_below,
            board_thickness=board_thickness,
            fit_tolerance=fit_tolerance,
            corner_radius=corner_radius,
            support_radius=support_radius,
            wall_width=wall_width);