fit sonar arm to deck holder more snuggly

[challenge-bot] / 3d-printables / sonar-table-top-holder.scad

// challenge-bot
// GNU AGPLv3 (or later at your option)
// project available at these locations:
// https://gitorious.org/ozzloy/challenge-bot
// https://github.com/waynegramlich/challenge-bot

$fn = 60;

// 3/16 inch in mm deck_depth = 4.7625;
// 1/4 inch in mm = 6.35
// subtract a little to be a squeeze fit
deck_depth = 4.7625 - 0.4;
// sonar sensor measurements taken with calipers:
//  10.82 in between, 42.33 outside, 15.82 diameter
// measured diameter of 15.82 with calipers,
//  but when printed ends up being too small, so add some
sonar_diameter = 15.82 + 0.6;
sonar_radius = sonar_diameter / 2;
sonar_height = 13.8;
between_sonar_centers = sonar_diameter + 10.82;
// the sonar cylinders are placed on the pcb at slightly different positions
//  from one sensor to the next, so this allows for that variance.
between_sonar_centers_variance = 2;
// keep at least this much plastic surrounding the sonar cylinder on all sides
buffer = 3;
sonar_holder_length = buffer + between_sonar_centers + sonar_diameter + buffer;
sonar_holder_width = buffer + sonar_diameter + buffer;
// sonar_holder_depth is deck_depth minus a little bit to make arm fit
//  into deck holder
sonar_holder_depth = deck_depth - 0.7;

deck_holder_length = sonar_holder_depth * 2 + deck_depth + 15;

module sonars(){
  translate([between_sonar_centers / 2, 0, 0]){
    cylinder(r = sonar_radius, h = sonar_height);}
  // for the variance with which the physical sonar cylinders are placed
  translate([between_sonar_centers / 2 - between_sonar_centers_variance, 0, 0]){
    cylinder(r = sonar_radius, h = sonar_height);
    translate([0, -sonar_radius, 0]){
      cube([between_sonar_centers_variance, sonar_diameter, sonar_height]);}}
  translate([-between_sonar_centers / 2, 0, 0]){
    cylinder(r = sonar_radius, h = sonar_height);}}

module sonar_holder(){
  elbow_length = deck_depth + 0.5;
  difference(){
    cube([sonar_holder_length, sonar_holder_width, sonar_holder_depth]);
    translate([sonar_holder_length / 2, sonar_holder_width / 2, -0.05]){
      sonars();}}
  translate([sonar_holder_length, 0, 0]){
    cube([elbow_length,
          deck_depth,
          sonar_holder_depth]);
    translate([elbow_length, 0, 0]){
      linear_extrude(height = sonar_holder_depth){
        polygon([[0, 0],
                 [sonar_holder_depth, 0],
                 [sonar_holder_depth, sonar_holder_width / 2],
                 [0, sonar_holder_width / 2 + sonar_holder_depth]]);}
      translate([0, (sonar_holder_width + sonar_holder_depth) / 2, 0]){
        cube([sonar_holder_depth / 2,
              (sonar_holder_width - sonar_holder_depth) / 2 + 0.8,
              sonar_holder_depth]);}
      translate([-1.7, sonar_holder_width + 0.8, 0]){
        linear_extrude(height = sonar_holder_depth){
          polygon([[0, 0],
                   [sonar_holder_depth / 2 + 1.7, 4],
                   [sonar_holder_depth / 2 + 1.7, 0]]);}}}}}

module deck_holder(){
  deck_holder_width = sonar_holder_width - deck_depth;
  linear_extrude(height = deck_holder_width){
    difference(){
      square([deck_holder_length, sonar_holder_depth * 2 + deck_depth]);
      translate([sonar_holder_depth, sonar_holder_depth]){
        square(deck_depth);}
      translate([sonar_holder_depth * 2 + deck_depth, sonar_holder_depth]){
        square([deck_holder_length - (sonar_holder_depth * 2 + deck_depth),
                deck_depth]);}}}}

deck_holder();
translate([0, sonar_holder_depth * 2 + deck_depth + 2, 0]){
  sonar_holder();}