make sonar holder 3d printable without overhang

diff --git a/sonar-table-top-holder.scad b/sonar-table-top-holder.scad
index 18efe08119ee219a31d1a4e182dc2d4fae3d78a0..4fa2dda21b645e412b2631410c39a66acd4a448b 100644 (file)
--- a/sonar-table-top-holder.scad
+++ b/sonar-table-top-holder.scad
@@ -4,28 +4,52 @@
 // https://gitorious.org/ozzloy/challenge-bot
 // https://github.com/waynegramlich/challenge-bot
 
-
 // sonar sensor measurements from https://www.thingiverse.com/thing:92869,
-//  released under GPL.
-deck_depth = 4.7625; // 3/8 inch in mm
+
+// 3/8 inch in mm
+deck_depth = 4.7625;
 sonar_plate_width = 20;
 sonar_plate_length = 45;
-sonar_plate_height = 1.2;
 sonar_sensor_radius = 8;
 sonar_sensor_height = 13.8;
-sonar_holder_length = sonar_plate_length + 30;
+sonar_holder_length = sonar_plate_length + 10;
+sonar_holder_width = sonar_plate_width + 3;
 sonar_holder_depth = 3;
+between_sensor_centers = 27;
+
+module sensors(){
+  translate([between_sensor_centers / 2, 0, 0]){
+    cylinder(r = sonar_sensor_radius, h = sonar_sensor_height);}
+  translate([-between_sensor_centers / 2, 0, 0]){
+    cylinder(r = sonar_sensor_radius, h = sonar_sensor_height);}}
+
+module deck_holder(){
+  deck_holder_length = 25;
+  deck_holder_width = sonar_holder_width;
+  cube([deck_holder_length, deck_holder_width, sonar_holder_depth]);
+  translate([0, 0, sonar_holder_depth]){
+    cube([deck_depth, deck_holder_width, deck_depth]);
+    translate([0, 0, deck_depth]){
+      cube([deck_holder_length, deck_holder_width, sonar_holder_depth]);}}}
+
+module sonar_table_top_holder(){
+  difference(){
+    union(){
+      cube([sonar_holder_length, sonar_holder_width, sonar_holder_depth]);
+      translate([sonar_holder_length, 0, 0]){
+        deck_holder();}}
+    translate([between_sensor_centers / 2 + sonar_sensor_radius + 3,
+               sonar_holder_width / 2,
+               -1]){
+      sensors();}
+    // cut out a bit of the circle to make it 3d printable,
+    //  no severe overhang
+    translate([3 + sonar_sensor_radius,
+               sonar_holder_width - 3.025,
+               sonar_holder_depth / 2 - 0.025]){
+      cube([10, 6.1, sonar_holder_depth + .1], center = true);
+      translate([between_sensor_centers, 0, 0]){
+        cube([10, 6.1, sonar_holder_depth + .1], center = true);}}}}
 
-difference (){
-  union(){
-    cube([sonar_holder_length, sonar_plate_width, sonar_holder_depth]);
-    translate([sonar_plate_length + 5, 0, sonar_holder_depth]){
-      cube([5, sonar_plate_width, deck_depth]);
-      translate([0, 0, deck_depth]){
-        cube([sonar_holder_length - sonar_plate_length - 5,
-              sonar_plate_width,
-              sonar_holder_depth]);}}}
-  translate([45/2 - 13.5, 10, 0]){
-    cylinder(r=sonar_sensor_radius, h = sonar_sensor_height, center = true);}
-  translate([45/2 + 13.5, 10, 0]){
-    cylinder(r=sonar_sensor_radius, h = sonar_sensor_height, center = true);}}
+rotate([90, 0, 0]){
+  sonar_table_top_holder();}