// 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

// use $fn = 20 while developing, 100 when about to print
//  20 will make previews fast
//  100 will make printing smooth
$fn = 100;

use <qr.scad>

qr_size = 54;
qr_height = 2;

wall_width = 3;

wheel_width = 6;
wheel_radius = sqrt(2 * pow(qr_size / 2, 2)) + wall_width / 2;

motor_shaft_radius = 3.7;
motor_shaft_flat_width = 4.8;

tread_radius = 2.5 / 2;

module mounting_screw_flat(){
  square(2, center = true);}

module motor_shaft_flat(radius, flat_width){
  intersection(){
    circle(radius);
    square([flat_width, radius * 2], center = true);}}

module motor_shaft(radius,
                   flat_width,
                   shaft_length){
  linear_extrude(height = shaft_length){
    motor_shaft_flat(radius, flat_width);}}

module rim(radius, wall_width, wheel_width){
  linear_extrude(height = wheel_width){
    difference(){
      circle(radius);
      circle(radius - wall_width);}}}

module motor_shaft_holder_flat(radius, flat_width, wall_width){
  difference(){
    motor_shaft_flat(radius + wall_width,
                     flat_width + wall_width);
    motor_shaft_flat(radius, flat_width);}}

module motor_shaft_holder(radius, flat_width, wall_width, height){
  linear_extrude(height = height){
    motor_shaft_holder_flat(radius, flat_width, wall_width);}}

module tread(wheel_radius, tread_radius){
  rotate_extrude(convexity = 10){
    translate([wheel_radius, 0]){
      circle(tread_radius);}}}

module wheel_black(radius,
                   width,
                   shaft_radius,
                   shaft_flat_width,
                   wall_width,
                   tread_radius){
  color("black"){
    difference(){
      rim(radius, wall_width, width);
      translate([0, 0, width / 2]){
        tread(radius, tread_radius);}}
    linear_extrude(height = qr_height){
      difference(){
        qr_black_flat();
        mounting_screw_flat();}}
    translate([0, 0, qr_height]){
      motor_shaft_holder(shaft_radius,
                         shaft_flat_width,
                         wall_width,
                         width - qr_height);}}}

module wheel_white(){
  color("white"){
    linear_extrude(height = qr_height){
      difference(){
        qr_white_flat();
        mounting_screw_flat();}}}}

module wheel(radius,
             width,
             shaft_radius,
             shaft_flat_width,
             wall_width,
             tread_radius){
  wheel_black(radius,
              width,
              shaft_radius,
              shaft_flat_width,
              wall_width,
              tread_radius);
  wheel_white();}

wheel(wheel_radius,
      wheel_width,
      motor_shaft_radius,
      motor_shaft_flat_width,
      wall_width,
      tread_radius);