g_fn = 64;
g_rounding = 1;
g_button_d = 8;
g_button_h = 12;
g_contact_h = 5.0;


module spherical_segment(d1, d2, h)
{
    r1=d1/2;
    r2=d2/2;
    H=(r2^2 - r1^2 - h^2) / (2*h);
    R=sqrt(H^2 + r2^2);

    intersection() {
        translate([0,0,0]) cylinder(h=h, d=d2, center=false, $fn=g_fn);
        translate([0,0,-H]) sphere(r=R, $fn=g_fn);
    }
}

difference() {
    union() {
        cylinder(h=2, d=g_button_d+2, center=false, $fn=g_fn);
        cylinder(h=g_button_h-g_rounding, d=g_button_d, center=false, $fn=g_fn);
        translate([0 ,0, g_button_h-g_rounding]) spherical_segment(g_button_d-g_rounding, g_button_d, g_rounding);
    }
    cylinder(h=g_button_h-2, d=g_button_d-2, center=false, $fn=g_fn);   
}


g_contact_support_h = g_button_h - 2;
translate([0, 0, (g_contact_support_h+g_contact_h) / 2]) {
    cube([g_button_d-1, 1.5, (g_contact_support_h-g_contact_h)], center=true);
    cube([1.5, g_button_d-1, (g_contact_support_h-g_contact_h)], center=true);
}