Generate a basic case bottom with PCB mounting holes

openscad/.gitignore

@@ -1,2 +1,2 @@
 *.stl
-pcb.scad
+pcb_dimensions.scad

openscad/Makefile

@@ -2,11 +2,11 @@
 
 all: case.stl
 
-pcb.scad: generate.py ../kicad/Digital\ Audio\ Switch.kicad_pcb
+pcb_dimensions.scad: generate.py ../kicad/Digital\ Audio\ Switch.kicad_pcb
 	python3 $< > $@
 
-case.stl: case.scad pcb.scad
+case.stl: case.scad pcb_dimensions.scad
 	openscad -o $@ case.scad
 
 clean:
-	rm -f case.stl pcb.scad
+	rm -f case.stl pcb_dimensions.scad

openscad/case.scad

@@ -1,9 +1,52 @@
 $fn = 50;
 
-use <pcb.scad>;
+include <pcb_mount.scad>;
+
+TOLERANCE=0.5;
+
+wall_width = 3;
+side_padding = 10;
+case_width = pcb_width + (wall_width * 2) + (TOLERANCE * 2) + (side_padding * 2);
+case_depth = pcb_height + (wall_width * 2) + (TOLERANCE * 2);
+bottom_height = 30;
+pcb_spacing = 10;
+pcb_thickness = 1.6;
+
+inside_offset = [wall_width + TOLERANCE + side_padding,wall_width + TOLERANCE,wall_width];
+
+color("purple")
+translate(inside_offset)
+pcb_mount(w=wall_width,h=pcb_spacing);
 
 color("green", 0.5)
-translate([0,0,10])
-    pcb(1.6);
+translate(inside_offset + [0,0,pcb_spacing]) {
+  difference() {
+    cube([pcb_width, pcb_height, pcb_thickness]);
+    translate([0,0,-0.5])
+      drill_hole_cutouts(h=pcb_thickness + 1);
+  }
+}
+module rounded_box(box, r) {
+  hull() {
+    cylinder(r=r,h=box.z);
+    translate([0,box.y])
+      cylinder(r=r,h=box.z);
+    translate([box.x,0])
+      cylinder(r=r,h=box.z);
+    translate([box.x, box.y])
+      cylinder(r=r,h=box.z);
+  }
+}
 
-mounting_supports(h=10,r=4);
+difference() {
+  rounded_box(box=[case_width, case_depth, bottom_height], r=wall_width);
+  translate([wall_width,wall_width,wall_width + 1])
+    rounded_box(box=[pcb_width + (TOLERANCE * 2) + (side_padding * 2),
+                     pcb_height + (TOLERANCE * 2),
+                     bottom_height],
+                r=wall_width);
+  translate(inside_offset - [0,0,wall_width + 0.5]) {
+    drill_hole_cutouts(h=pcb_spacing);
+    posts(w=wall_width, h=wall_width/2 + 0.5);
+  }
+}

openscad/generate.py

@@ -1,5 +1,7 @@
 import sexpdata as s
 
+TOLERANCE = 0.2
+
 
 def cadr(x):
     return s.car(s.cdr(x))
@@ -31,9 +33,8 @@ width = end_x - start_x
 height = end_y - start_y
 print(
     f"""
-module board() {{
-    square([{width}, {height}]);
-}}
+pcb_width = {width};
+pcb_height = {height};
     """.strip()
 )
 
@@ -51,45 +52,9 @@ for hole in footprints:
         [[pad_x, pad_y]] = [s.cdr(x) for x in pad if s.car(x) == s.Symbol("at")]
         drills = [cadr(x) for x in pad if s.car(x) == s.Symbol("drill")]
         for diameter in drills:
-            # print([hole_x + pad_x, hole_y + pad_y, diameter])
             pos_x = (hole_x + pad_x) - start_x
             pos_y = (hole_y + pad_y) - start_y
-            holes.append((pos_x, pos_y, diameter))
+            holes.append([pos_x, pos_y, diameter])
 
-print("module mounting_holes() {")
-for pos_x, pos_y, diameter in holes:
-    print(f"translate([{pos_x}, {pos_y}]) circle(d={diameter});")
-print("}")
-
-print("module mounting_posts(r, h) {")
-for pos_x, pos_y, diameter in holes:
-    print(
-        " ".join(
-            [
-                f"translate([{pos_x}, {pos_y}]) ",
-                f"linear_extrude(h)",
-                f"circle(d={diameter} + (r * 2));",
-            ]
-        )
-    )
-
-print("}")
-
-print(
-    """
-module pcb(h=1) {
-    linear_extrude(h)
-    difference() {
-        board();
-        mounting_holes();
-    }
-}
-
-module mounting_supports(r, h) {
-    difference() {
-        mounting_posts(r=r, h=h);
-        linear_extrude(h+1) mounting_holes();
-    }
-}
-"""
-)
+# Y coordinates are inverted between KiCad and OpenSCAD
+print(f"drill_holes = {[[[x, -y + height], r] for x, y, r in holes]};")

openscad/pcb_mount.scad

@@ -0,0 +1,57 @@
+include <pcb_dimensions.scad>;
+
+TOLERANCE=0.2;
+
+h=10;
+w=3;
+
+module pcb_mount(w=w,h=h) {
+  difference() {
+    union() {
+      posts(w=w,h=h);
+      frame(w=w);
+    }
+    drill_hole_cutouts(h=h);
+  }
+}
+
+module drill_hole_cutouts(h=h) {
+  for (hole=drill_holes) {
+    pos = hole[0];
+    diameter = hole[1] + TOLERANCE;
+    translate([pos.x, pos.y, -0.5]) {
+      cylinder(d=diameter,h=h + 1);
+    }
+  }
+}
+
+module posts(w=w,h=h) {
+  // Posts
+  for (hole=drill_holes) {
+    pos = hole[0];
+    diameter = hole[1] + TOLERANCE;
+    translate(pos) {
+      difference() {
+        cylinder(d=diameter + (w * 2), h=h);
+        translate([0,0,-0.5])
+          cylinder(d=diameter,h=h + 1);
+      }
+    }
+  }
+}
+
+module frame(w=w) {
+  min_x = min([for (hole=drill_holes) hole[0].x]);
+  min_y = min([for (hole=drill_holes) hole[0].y]);
+  max_x = max([for (hole=drill_holes) hole[0].x]);
+  max_y = max([for (hole=drill_holes) hole[0].y]);
+  max_diameter = max([for (hole=drill_holes) hole[1]]);
+
+  translate([min_x - (w / 2), min_y - (w / 2)]) {
+    difference() {
+      cube([max_x - min_x + w, max_y - min_y + w, w]);
+      translate([w, w, -0.5])
+        cube([max_x - min_x - w, max_y - min_y - w, w + 1]);
+    }
+  }
+}