$fn=60;

// Physical dimensions
EXTRUSION_WIDTH = 40;
EXTRUSION_HEIGHT = 40;
EXTRUSION_GROOVE_WIDTH = 8.2;

MOTOR_WIDTH = 43.0;
MOTOR_HEIGHT = 43.0;
MOTOR_DEPTH = 40.0;
MOTOR_CORNER = 4.5;
MOTOR_SHAFT_HOLE_DIAMETER = 24;

BOLT_HOLE_DIAMETER = 6.4;       // M6
BOLT_HOLE_HEAD_DIAMETER = 11;       // M6


// Parameters
CORNER_SIZE = 5.0;                      // Part corner size
MOTOR_TO_BORDER_CLEARANCE = 8.0;
CHAMFER_SIZE = 0.4;
EXTRUSION_BORDER_CLEARANCE = 1;         // Distance between extrusion and part borders
EXTRUSION_GROOVE_SLIDE_CLEARANCE = 0.2; // Slide to groove clearance
EXTRUSION_GROOVE_SLIDE_DEPTH = 2;       // Slide depth

// Variables
total_width = EXTRUSION_WIDTH - EXTRUSION_BORDER_CLEARANCE + MOTOR_WIDTH + MOTOR_TO_BORDER_CLEARANCE;
total_height = EXTRUSION_HEIGHT - EXTRUSION_BORDER_CLEARANCE + MOTOR_HEIGHT + MOTOR_TO_BORDER_CLEARANCE;


base_p = [
            [0,                         CORNER_SIZE],
            [0,                         total_height - CORNER_SIZE],
            [CORNER_SIZE,               total_height],
            [total_width - CORNER_SIZE, total_height],
            [total_width,               total_height - CORNER_SIZE],
            [total_width,               CORNER_SIZE],
            [total_width - CORNER_SIZE, 0],
            [CORNER_SIZE, 0]
        ];


motor_p = [
            [0,                             MOTOR_CORNER],
            [0,                             MOTOR_HEIGHT - MOTOR_CORNER],
            [MOTOR_CORNER,                  MOTOR_HEIGHT],
            [MOTOR_WIDTH - MOTOR_CORNER,    MOTOR_HEIGHT],
            [MOTOR_WIDTH,                   MOTOR_HEIGHT - MOTOR_CORNER],
            [MOTOR_WIDTH,                   MOTOR_CORNER],
            [MOTOR_WIDTH - MOTOR_CORNER,    0],
            [MOTOR_CORNER,                  0]
          ];


module hexagon(ri =  1.0)   // inner radius of hexagon
{
	ra = ri*2/sqrt(3);
	circle(r = ra, $fn=6);
}

module m3nut(height)
{
    linear_extrude(height) hexagon(5.6 / 2);
}


module groove(s)
{
    groove_p = [
                 [0, 0],
                 [0, EXTRUSION_GROOVE_SLIDE_DEPTH - 0.6],
                 [0.6, EXTRUSION_GROOVE_SLIDE_DEPTH],
                 [EXTRUSION_GROOVE_WIDTH - 0.6, EXTRUSION_GROOVE_SLIDE_DEPTH],
                 [EXTRUSION_GROOVE_WIDTH, EXTRUSION_GROOVE_SLIDE_DEPTH - 0.6],
                 [EXTRUSION_GROOVE_WIDTH, 0],
               ];

    translate([0,s,0])
    rotate([90,0,0])
    linear_extrude(s)
    polygon(groove_p);
}

module base()
{

        union()
        {
            hull()
            {
                linear_extrude(2)
                offset(-4)
                polygon(base_p);

                translate([0, 0, 2])
                linear_extrude(14)
                offset(-1.75)
                polygon(base_p);

                translate([0, 0, 16])
                linear_extrude(8)
                polygon(base_p);
            }
            
            // Grooves
            translate([EXTRUSION_WIDTH / 2 - EXTRUSION_GROOVE_WIDTH / 2 - EXTRUSION_BORDER_CLEARANCE, 0, 2+14+8])
            groove(10.5 + EXTRUSION_HEIGHT - EXTRUSION_BORDER_CLEARANCE);

            translate([EXTRUSION_WIDTH / 2 - EXTRUSION_GROOVE_WIDTH / 2 - EXTRUSION_BORDER_CLEARANCE, 
                       10.5 + EXTRUSION_HEIGHT - EXTRUSION_BORDER_CLEARANCE + 9, 
                       2+14+8])
            groove(11);

            translate([EXTRUSION_WIDTH / 2 - EXTRUSION_GROOVE_WIDTH / 2 - EXTRUSION_BORDER_CLEARANCE, 10.5 + EXTRUSION_HEIGHT - EXTRUSION_BORDER_CLEARANCE + 9 + 11 + 9, 2+14+8])
            groove(11.5);

            translate([0, EXTRUSION_HEIGHT / 2 - EXTRUSION_GROOVE_WIDTH / 2 - EXTRUSION_BORDER_CLEARANCE + EXTRUSION_GROOVE_WIDTH, 2+14+8])
            rotate([0,0,-90])
            groove(10.5 + EXTRUSION_HEIGHT - EXTRUSION_BORDER_CLEARANCE);

            translate([10.5 + EXTRUSION_WIDTH - EXTRUSION_BORDER_CLEARANCE + 9, EXTRUSION_HEIGHT / 2 - EXTRUSION_GROOVE_WIDTH / 2 - EXTRUSION_BORDER_CLEARANCE + EXTRUSION_GROOVE_WIDTH, 2+14+8])
            rotate([0,0,-90])
            groove(11);

            translate([10.5 + EXTRUSION_WIDTH - EXTRUSION_BORDER_CLEARANCE + 9 + 11 + 9, EXTRUSION_HEIGHT / 2 - EXTRUSION_GROOVE_WIDTH / 2 - EXTRUSION_BORDER_CLEARANCE + EXTRUSION_GROOVE_WIDTH, 2+14+8])
            rotate([0,0,-90])
            groove(11.5);
        }

}


motor_shaft_hole_radius = MOTOR_SHAFT_HOLE_DIAMETER / 2;
motor_center_x = EXTRUSION_WIDTH - EXTRUSION_BORDER_CLEARANCE + MOTOR_WIDTH / 2;
motor_center_y = EXTRUSION_HEIGHT - EXTRUSION_BORDER_CLEARANCE + MOTOR_HEIGHT / 2;


difference()
{
    base();

    translate([-EXTRUSION_BORDER_CLEARANCE, -EXTRUSION_BORDER_CLEARANCE, -1])
    cube([EXTRUSION_WIDTH, EXTRUSION_HEIGHT, 29]);
        
    translate([EXTRUSION_WIDTH - EXTRUSION_BORDER_CLEARANCE, EXTRUSION_HEIGHT - EXTRUSION_BORDER_CLEARANCE, 5])
    linear_extrude(20)
    polygon(motor_p);

    // Motor holes
    translate([motor_center_x, motor_center_y, -1])
    cylinder(20, r=motor_shaft_hole_radius);
    
    translate([motor_center_x - 31/2, motor_center_y - 31/2, -1])
    cylinder(20, r=3.4/2);
    
    translate([motor_center_x + 31/2, motor_center_y - 31/2, -1])
    cylinder(20, r=3.4/2);

    translate([motor_center_x - 31/2, motor_center_y + 31/2, -1])
    cylinder(20, r=3.4/2);

    translate([motor_center_x + 31/2, motor_center_y + 31/2, -1])
    cylinder(20, r=3.4/2);

    // Chamfers
    translate([motor_center_x, motor_center_y, -0.01])
    cylinder(1, motor_shaft_hole_radius+0.5, motor_shaft_hole_radius);
    
    translate([motor_center_x - 31/2, motor_center_y - 31/2, -0.01])
    cylinder(1, (3.4+0.5)/2);
    
    translate([motor_center_x + 31/2, motor_center_y - 31/2, -0.01])
    cylinder(1, (3.4+0.5)/2);

    translate([motor_center_x - 31/2, motor_center_y + 31/2, -0.01])
    cylinder(1, (3.4+0.5)/2);

    translate([motor_center_x + 31/2, motor_center_y + 31/2, -0.01])
    cylinder(1, (3.4+0.5)/2);
    

    // Groove holes
    translate([EXTRUSION_WIDTH / 2 - EXTRUSION_BORDER_CLEARANCE, 10.5 + EXTRUSION_HEIGHT - EXTRUSION_BORDER_CLEARANCE + 4.5, 11.2])
    cylinder(35, r = BOLT_HOLE_DIAMETER / 2);

    translate([EXTRUSION_WIDTH / 2 - EXTRUSION_BORDER_CLEARANCE, 10.5 + EXTRUSION_HEIGHT - EXTRUSION_BORDER_CLEARANCE + 9 + 11 + 4.5, 11.2])
    cylinder(35, r = BOLT_HOLE_DIAMETER / 2);

    translate([10.5 + EXTRUSION_WIDTH - EXTRUSION_BORDER_CLEARANCE + 4.5, EXTRUSION_HEIGHT / 2 - EXTRUSION_BORDER_CLEARANCE, 11.2])
    cylinder(35, r = BOLT_HOLE_DIAMETER / 2);

    translate([10.5 + EXTRUSION_WIDTH - EXTRUSION_BORDER_CLEARANCE + 9 + 11 + 4.5, EXTRUSION_HEIGHT / 2 - EXTRUSION_BORDER_CLEARANCE, 11.2])
    cylinder(35, r = BOLT_HOLE_DIAMETER / 2);


    // Bolt head holes
    translate([EXTRUSION_WIDTH / 2 - EXTRUSION_BORDER_CLEARANCE, 10.5 + EXTRUSION_HEIGHT - EXTRUSION_BORDER_CLEARANCE + 4.5, -1])
    cylinder(12, r = BOLT_HOLE_HEAD_DIAMETER / 2);

    translate([EXTRUSION_WIDTH / 2 - EXTRUSION_BORDER_CLEARANCE, 10.5 + EXTRUSION_HEIGHT - EXTRUSION_BORDER_CLEARANCE + 9 + 11 + 4.5, -1])
    cylinder(12, r = BOLT_HOLE_HEAD_DIAMETER / 2);

    translate([10.5 + EXTRUSION_WIDTH - EXTRUSION_BORDER_CLEARANCE + 4.5, EXTRUSION_HEIGHT / 2 - EXTRUSION_BORDER_CLEARANCE, -1])
    cylinder(12, r = BOLT_HOLE_HEAD_DIAMETER / 2);

    translate([10.5 + EXTRUSION_WIDTH - EXTRUSION_BORDER_CLEARANCE + 9 + 11 + 4.5, EXTRUSION_HEIGHT / 2 - EXTRUSION_BORDER_CLEARANCE, -1])
    cylinder(12, r = BOLT_HOLE_HEAD_DIAMETER / 2);


    // Bold head chamfers
    translate([EXTRUSION_WIDTH / 2 - EXTRUSION_BORDER_CLEARANCE, 10.5 + EXTRUSION_HEIGHT - EXTRUSION_BORDER_CLEARANCE + 4.5, -0.01])
    cylinder(1, (BOLT_HOLE_HEAD_DIAMETER+1) / 2, BOLT_HOLE_HEAD_DIAMETER / 2);

    translate([EXTRUSION_WIDTH / 2 - EXTRUSION_BORDER_CLEARANCE, 10.5 + EXTRUSION_HEIGHT - EXTRUSION_BORDER_CLEARANCE + 9 + 11 + 4.5, -0.01])
    cylinder(1, (BOLT_HOLE_HEAD_DIAMETER+1) / 2, BOLT_HOLE_HEAD_DIAMETER / 2);

    translate([10.5 + EXTRUSION_WIDTH - EXTRUSION_BORDER_CLEARANCE + 4.5, EXTRUSION_HEIGHT / 2 - EXTRUSION_BORDER_CLEARANCE, -0.01])
    cylinder(1, (BOLT_HOLE_HEAD_DIAMETER+1) / 2, BOLT_HOLE_HEAD_DIAMETER / 2);

    translate([10.5 + EXTRUSION_WIDTH - EXTRUSION_BORDER_CLEARANCE + 9 + 11 + 4.5, EXTRUSION_HEIGHT / 2 - EXTRUSION_BORDER_CLEARANCE, -0.01])
    cylinder(1, (BOLT_HOLE_HEAD_DIAMETER+1) / 2, BOLT_HOLE_HEAD_DIAMETER / 2);

}