# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1412768358 -7200
# Node ID 37592a06218d608b10faa86132b13442cc63e4cc
# Parent  73b9ec08020dc5e83bf764b46fbb914b77a4ec99
Rounded off the back PCB lugs for easier connection.
Reduced the rounding radius used on the back extension edges.

diff -r 73b9ec08020d -r 37592a06218d cartridge.scad
--- a/cartridge.scad	Wed Oct 08 00:43:47 2014 +0200
+++ b/cartridge.scad	Wed Oct 08 13:39:18 2014 +0200
@@ -50,9 +50,14 @@
 	ro = rr;
 	extra = 0.1;
 
-	groove_rr = 0.5;
+	groove_rr = 0.2;
 	groove_ro = groove_rr;
 
+	pcb_lug_rr = 0.5;
+	pcb_lug_ro = pcb_lug_rr;
+
+	/* A fillet performs rounding using a quarter segment of a cylinder. */
+
 	module fillet(r, h) {
 		translate([0, 0, -h/2])
 			difference() {
@@ -68,6 +73,20 @@
 		}
 	}
 
+	module fillet_torus(radius, rounding) {
+		difference() {
+			cube_at((radius + extra) * 2, (radius + extra) * 2, rounding + extra,
+				0, 0, 1,
+				0, 0, 0);
+			union() {
+				rotate_extrude(convexity = 10)
+					translate([radius - rounding, 0, 0])
+						circle(r = rounding);
+				cylinder(r = radius - rounding, h = rounding);
+			}
+		}
+	}
+
 	/*
 	Justify an object of the given dimensions, according to the given
 	factors (where 1 indicates moving the object to the positive side of an
@@ -363,6 +382,8 @@
 							0, 0, 0);
 					}
 					cylinder(h=pcb_lug_depth, r=pcb_lug_inner_radius);
+					translate([0, 0, pcb_lug_depth - pcb_lug_ro])
+						fillet_torus(pcb_lug_outer_radius, pcb_lug_rr);
 				}
 	}