N=3;//number of cup

cup_internal_diameter=25;

cup_tickness=2;

arm_lenght=24.5;

center_axle_external_diameter=27.85;

center_axle_internal_diameter=2.75;

center_axle_height=24;

magnet_diameter=4;

magnet_axle_distance=10;

screw_diam=1.75;

$fn=200;

// Length of the cone

egg_length = 42; // [10:2:200]

// Number of steps to sample the half profile of the egg

steps = 150; // [50:5:300]

//center axle

difference() {

    //Make the top part of the egg:

translate([0,0,-egg_length/2])

difference()

{

  solid_egg(length=egg_length, offset=0, steps=steps);

 //the cube for cutting the egg into two pieces:

 translate([-egg_length/2,-egg_length/2,-egg_length/2])

  cube([egg_length, egg_length, egg_length]);

}

 ///cone   

   //extrude

cylinder(h = 7.5, r=9, center =false);

  //axle  

cylinder(h = center_axle_height-4, r=center_axle_internal_diameter/2, center =false);

 //magnet

    rotate([0,0,40])

  translate([magnet_axle_distance, 0, 0])

    cylinder(h = center_axle_height, r=magnet_diameter/2, center =false); 

 //screw 

    translate([0, 0, 13])

    rotate([50,90,90])

    cylinder(h = 40, r=screw_diam/2, center =false); 

}

//cups 

for ( i = [0 : N-1] )

{

    //arm

    rotate( i * 360 / N, [0, 0, 1])

    translate(v = [arm_lenght+10, -3, 2.5])

    difference(){ 

    cube (size = [arm_lenght+20,5,5], center =true);

    //clear inner sphere arm

        translate(v = [15, 2, 11])

    sphere(r = cup_internal_diameter/2, $fn=100); 

    }

    //cup

    rotate( i * 360 / N, [0, 0, 1])

    translate(v = [arm_lenght+cup_internal_diameter, 0, 14.5]) 

    difference()  {

    sphere(r = cup_internal_diameter/2+cup_tickness, $fn=100);

    union() {

       sphere(r = cup_internal_diameter/2, $fn=100); 

       translate(v = [0, 10, 0])

        //cut half sphere

       cube (size = [cup_internal_diameter*2,21,cup_internal_diameter*2], center =true);

    }//end union

    }//end diff

}//end for

//////////////////////////////////////

// taken form https://www.thingiverse.com/thing:2797274/

//////////////////////////////////////

// Egg profile computing function

function egg(x, l)= 0.9*l*pow(1-x/l, 2/3)*sqrt(1-pow(1-x/l, 2/3));

// Create egg profile

module egg_profile(length=egg_length, offset=0, steps=steps) {

    ss = length / (steps-1); // step size

    v1 = [for (x=[0:ss:length]) [egg(x, length), x + offset]];

    // Make absolute sure the last point brings the profile

    // back to the axis

    v2 = concat(v1, [[0, length + offset]]);

    // Close the loop

    v3 = concat(v2, [[0, offset]]);

        polygon(points = v3);

}

// Create a solid egg part

module solid_egg(length=egg_length, offset=0, steps=steps) {

    rotate_extrude(convexity = 10) {

        egg_profile(length=length, offset=offset, steps=steps);

    }

}