Servo arm + Thickness bug correction

cad/leg.scad

@@ -44,7 +44,7 @@ module arm(width, length, height, hole = [5, 5], gap_width = 0, gap_length = 0)
 // Long arm
 module long_arm() {
     difference() {
-        arm(15, 135, 4, [5, 2], 0, 0);
+        arm(15, 135, ARM_THICKNESS, [5, 2], 0, 0);
 
         translate([0, 12.5, -1]) {
             cylinder(h = 20, r1 = 2.5, r2 = 2.5);
@@ -58,7 +58,7 @@ module long_arm() {
 
 module short_arm() {
     difference() {
-        arm(15, 80, 4, [5, 5], 0, 0);
+        arm(15, 80, ARM_THICKNESS, [5, 5], 0, 0);
         connection();
     }
 }
@@ -181,9 +181,9 @@ if (0) {
         }
     }
 } else {
-    //main_arm();
+    main_arm();
     //long_arm();
-    short_arm();
+    //short_arm();
     //spacer(ARMS_SPACING, ARM_WIDTH, ARM_THICKNESS);
     //spacer(ARMS_SPACING + ARM_THICKNESS * 2 - 1, 15, ARM_THICKNESS);
 }

cad/lib/servo_arm.scad

@@ -0,0 +1,159 @@
+$fn = 40;
+
+HOLDER_THICKNESS = 1.1;
+SCREW_DIAMETER = 2.5;
+
+// @Todo: add HOLDER_THICKNESS and SCREW_DIAMETER in Spline definition and eventually clear
+
+/**
+ *  Head / Tooth parameters
+ *  Futaba 3F Standard Spline
+ *  http://www.servocity.com/html/futaba_servo_splines.html
+ *  external diameter, tooth count, tooth height, tooth length, tooth width, thickness
+ */
+FUTABA_3F_SPLINE = [5.92, 25, 0.3, 0.7, 0.1, 4];
+
+module servo_futaba_3f(length, count) {
+    servo_arm(FUTABA_3F_SPLINE, [length, count]);
+}
+
+module servo_standard(length, count) {
+    servo_futaba_3f(length, count);
+}
+
+/**
+ *  Tooth
+ *
+ *    |<-w->|
+ *    |_____|___
+ *    /     \  ^h
+ *  _/       \_v
+ *   |<--l-->|
+ *
+ *  - tooth length (l)
+ *  - tooth width (w)
+ *  - tooth height (h)
+ *  - thickness
+ *
+ */
+module servo_head_tooth(length, width, height, thickness) {
+    linear_extrude(height = thickness) {
+        polygon([[-length / 2, 0], [-width / 2, height], [width / 2, height], [length / 2,0]]);
+    }
+}
+
+/**
+ *  With PLA material, use clear at 0.3
+ *  For ABS, use 0.2
+ */
+module servo_head(params, clear = 0.2) {
+
+    diameter = params[0];
+    count = params[1];
+    height = params[2];
+    length = params[3];
+    width = params[4];
+    thickness = params[5];
+
+    % cylinder(r = diameter / 2, h = thickness + 1);
+
+    cylinder(r = diameter / 2 - height + 0.03 + clear, h = thickness);
+
+    for (i = [0 : count]) {
+        rotate([0, 0, i * (360 / count)]) {
+            translate([0, diameter / 2 - height + clear, 0]) {
+                servo_head_tooth(length, width, height, thickness);
+            }
+        }
+    }
+}
+
+/**
+ *  Servo hold
+ *  - Head / Tooth parameters
+ *  - Arms params (length and count)
+ */
+module servo_arm(params, arms) {
+
+    diameter = params[0];
+    count = params[1];
+    height = params[2];
+    length = params[3];
+    width = params[4];
+    thickness = params[5];
+
+    arm_length = arms[0];
+    arm_count = arms[1];
+
+    /**
+     *  Servo arm
+     *  - length is from center to last hole
+     */
+    module arm(length, width, head_height, thickness, hole_count = 1) {
+
+        screw_diameter = 2;
+
+        difference() {
+            union() {
+                cylinder(r = width / 2, h = thickness);
+
+                linear_extrude(height = thickness) {
+                    polygon([[-width / 2, 0], [-width / 3, length], [width / 3, length],[width / 2, 0]]);
+                }
+
+                translate([0, length, 0]) {
+                    cylinder(r = width / 3, h = thickness);
+                }
+
+                if (length >= 12) {
+                    translate([-thickness / 2 + 2, 3.8, -4]) {
+                        rotate([90, 0, 0]) {
+                            rotate([0, -90, 0]) {
+                                linear_extrude(height = thickness) {
+                                    polygon([[-length / 1.7, 4], [0, 4], [0, - head_height + 5], [-2, - head_height + 5]]);
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+
+            // Hole
+            for (i = [0 : hole_count - 1]) {
+                //translate([0, length - (length / hole_count * i), -1]) {
+                translate([0, length - (4 * i), -1]) {
+                    cylinder(r = screw_diameter / 2, h = 10);
+                }
+            }
+
+            cylinder(r = SCREW_DIAMETER / 2, h = 10);
+        }
+    }
+
+    difference() {
+        translate([0, 0, 0.1]) {
+            cylinder(r = diameter / 2 + HOLDER_THICKNESS, h = thickness + 1);
+        }
+
+        cylinder(r = SCREW_DIAMETER / 2, h = 10);
+
+        servo_head(params);
+    }
+
+    // Arm
+    translate([0, 0, thickness]) {
+        for (i = [0 : arm_count - 1]) {
+            rotate([0, 0, i * (360 / arm_count)]) {
+                arm(arm_length, diameter + HOLDER_THICKNESS * 2, thickness, 2);
+            }
+        }
+    }
+}
+
+module demo() {
+    rotate([0, 180, 0])
+        servo_standard(20, 4);
+}
+
+demo();
+

cad/servo_arm.scad

@@ -0,0 +1,7 @@
+
+use <lib/servo_arm.scad>
+
+rotate([0, 180, 0])
+    //servo_standard(8.5, 1);
+    servo_standard(14, 1);
+