draft=true;
layer_height=0.2; extrusion_width=0.4;
epsilon=0.01;
$fs=0.0125;

use <threads.scad>;
module pushfit_thread(h=10) {
 thr = 3/8 + .5/25.4;
 slit = 25.4*thr/2 + 0.4;
 if(draft) cylinder(d=thr*25.4,h=h);
 else english_thread(diameter=thr,threads_per_inch=28,length=h/25.4,internal=true);
 translate([-2,-slit,0]) cube([4,2*slit,h]);
}

module the_extruder(
 // motor properties
 gearbox_d = 36,
 mount_d = 28,					// the distance between opposite mounting holes
 mounthole_depth = 5,
 protrusion_d = 22, protrusion_h = 2.2,		// the dimensions of the protrusion on top of gearbox
 bore_d = 8, bore_l = 17.6,
 bore_dd = 7,
 // pulley properties
 pulley_d = 11.5, pulley_h=10,
 pulley_elevation = 1,				// pulley elevation above the protrusion
 teeth_elevation = 7.5,				// distance from the bottom of the pulley to its teeth
 // idler properties
 idler_d = 9.5, idler_h = 4, idler_id = 3,	// idler dimensions: outer and inner diameters and height
 // spring properties
 spring_d = 10, spring_lc = 9.6,		// spring diameter and compressed length
 // filament path properties
 filament_d = 1.75,
 filament_path_d = 2,
 filament_guide_d = 4,				// PTFE filament guide diameter
 // knob properties
 knob_h = 10,
 knob_bore_l = 4,
 knob_indent_d = 4,
 knob_indents = 12,

 // screw it
 mount_screw_d = 3, mount_screw_l = 20,
 mount_screwhead_d=6, mount_screwhead_h=3,

 // empty spaces
 idler_travel = 3,				// how far should idler travel when pressed
 idler_clearance=1,
 pulley_clearance=2,
 lever_v_clearance=.7,				// vertical clearance for the lever
 spring_d_clearance=1,
 protrusion_tolerance_h=.5,			// horizontal tolerance for the motor protrusion
 protrusion_tolerance_v=.5,			// vertical tolerance for the motor protrusion
 mount_screw_d_tolerance=.5,
 idler_v_tolerance=.5,
 knob_bore_d_tolerance=.6,

 what="lever",
 left=false,
 vitamins = true
) {
 lever_shell = mount_screwhead_h+0.5;
 lever_thickness=max(spring_d+layer_height*8,idler_h+idler_v_tolerance+2*lever_shell);
 lsd = idler_d-idler_clearance*2;
 longwing=gearbox_d/2+spring_d/2+lsd/2;
 h_ = (pulley_d+idler_d)/(2*sqrt(2));
 ri = sqrt( pow(h_,2) + pow(mount_d/2-h_,2) );
 spring_dl = idler_travel*longwing/ri;

 filament_elevation=protrusion_h+pulley_elevation+teeth_elevation;
 ls_z = filament_elevation; // leverspace mid-z
 body_h = max(protrusion_h+bore_l,mount_screw_l-mounthole_depth/2+mount_screwhead_h,ls_z*2);
 ls_h = lever_thickness+lever_v_clearance; // leverspace height

 module mirrorleft() {
  mirror([left?0:1,0,0]) children();
 }
 module place_idler() {
  rotate([0,0,45])
  translate([(pulley_d+idler_d)/2,0,0])
  children();
 }
 module finger_indent(d=lever_thickness,depth/*=1*/,r/*=15*/) {
  if(depth) {
   hh = (-4*pow(depth,2)+pow(d,2))/(8*depth);
   rr = depth+hh;
   translate([0,0,hh]) sphere(r=rr,$fn=2*PI*rr);
  }else if(r) {
   hh=sqrt(pow(r,2)-pow(d,2)/4);
   translate([0,0,hh]) sphere(r=r,$fn=2*PI*r);
  }
 }

 % if(vitamins) mirrorleft() {
  translate([0,0,-epsilon]) mirror([0,0,1]) cylinder(d=gearbox_d,h=1,$fn=60);
  for(zr=[0:90:359]) rotate([0,0,zr]) translate([mount_d/2,0,0])
   cylinder(d=mount_screw_d,h=20,$fn=30);
  translate([0,0,-epsilon]) cylinder(d=protrusion_d,h=protrusion_h,$fn=30);
  translate([0,0,protrusion_h]) {
   difference() {
    cylinder(d=bore_d,h=bore_l,$fn=30);
    translate([-bore_d/2-1,bore_dd-bore_d/2,-1])
    cube([bore_d+2,bore_d/2,bore_l+2]);
   }
   translate([0,0,pulley_elevation]) {
    cylinder(d=pulley_d,h=pulley_h,$fn=30);
    translate([0,0,teeth_elevation]) {
     place_idler() {
      cylinder(d=idler_d,h=idler_h,center=true,$fn=30);
      cylinder(d=idler_id,h=lever_thickness+2,center=true,$fn=30);
     }//place idler
     // filament path
     rotate([0,0,45]) translate([(pulley_d-filament_path_d)/2,0,0]) {
      rotate([90,0,0]) cylinder(d=filament_d,h=gearbox_d*2,center=true,$fn=15);
      rotate([-90,0,0])
      translate([0,0,mount_d/sqrt(2)/2+mount_screw_d])
      pushfit_thread();
     }
    }//translate teeth
   }//translate pulley
  }//translate protrusion
 }//vitamins

 module lever() {
  translate([0,0,protrusion_h+pulley_elevation+teeth_elevation]) {
   difference() {
    union() {
     hull() {
      place_idler()
      cylinder(d=lsd,h=lever_thickness,center=true,$fn=60);
      translate([mount_d/2,0,0])
      cylinder(d=lsd,h=lever_thickness,center=true,$fn=60);
     }//hull
     hull() {
      translate([mount_d/2,0,0])
      cylinder(d=lsd,h=lever_thickness,center=true,$fn=60);
      translate([mount_d/2,-longwing,0]) rotate([0,90,0])
      cylinder(d=lever_thickness,h=lsd,center=true,$fn=60);
     }//hull
    }//union
 
    // filament path
    place_idler() translate([-(idler_d+filament_path_d)/2,0,0]) rotate([90,0,0]) {
     cylinder(d=filament_path_d,h=3*gearbox_d,center=true,$fn=30);
     translate([0,-filament_path_d/2/sqrt(2),0]) rotate([0,0,45])
     cube(size=[filament_path_d/2,filament_path_d/2,3*gearbox_d],center=true);
    }
    
    // idler space and mounting hole
    place_idler() {
     difference() {
      cylinder(d=idler_d+idler_clearance*2,h=idler_h+idler_v_tolerance,center=true,$fn=60);
      // supports
      for(y=[-lsd/2+extrusion_width:(lsd-2*extrusion_width)/3:lsd/2-extrusion_width])
       translate([-lsd/2-1,y-extrusion_width/2,-idler_h/2-idler_v_tolerance/2-1])
       cube(size=[lsd+2,extrusion_width,idler_h+idler_v_tolerance+2]);
     }
     cylinder(d=mount_screw_d+mount_screw_d_tolerance,h=lever_thickness+2,center=true,$fn=30);
     translate([0,0,lever_thickness/2-mount_screwhead_h]) 
     cylinder(d=mount_screwhead_d,h=mount_screwhead_h+1,$fn=2*PI*mount_screwhead_d);
    }
    // mounting screw hole
    translate([mount_d/2,0,0])
    cylinder(d=mount_screw_d+mount_screw_d_tolerance,h=lever_thickness+2,center=true,$fn=2*PI*mount_screw_d);
    
    // lever end
    translate([mount_d/2,0,0]) rotate([0,90,0]) {
     translate([0,-longwing,lsd/2]) finger_indent(d=lever_thickness-1,r=15);
     translate([0,-longwing,0])
     mirror([0,0,1])
     difference() {
      cylinder(d=spring_d+spring_d_clearance,h=lsd,$fn=2*PI*spring_d);
      sphere(d=spring_d*3/4,$fn=PI*spring_d);
     }
    }//rotate-translate
   }//difference
   // bridging patch
   place_idler()
   translate([0,0,lever_thickness/2-mount_screwhead_h])
   mirror([0,0,1])
   cylinder(d=mount_screwhead_d,h=layer_height);
  }//translate
 }//lever module
 
 module body() {
  difference() {
   union() {
   cylinder(d=gearbox_d,h=body_h,$fn=2*PI*gearbox_d);
    // finger and spring support
    fsw = gearbox_d/2+mount_screwhead_d/2;
    translate([-gearbox_d/2,0,0]) difference() {
     union() {
      hull() {
       translate([0,-longwing,ls_z])
       rotate([0,90,0])
       cylinder(d=lever_thickness,h=fsw,$fn=2*PI*lever_thickness);
       hh=body_h-ls_z;
       translate([0,0,ls_z-lever_thickness/2])
       mirror([0,1,0]) cube(size=[fsw,longwing-hh+lever_thickness/sqrt(2),hh+lever_thickness/2]);
       hhh=ls_z;
       translate([0,0,0])
       mirror([0,1,0]) cube(size=[fsw,longwing-hhh+lever_thickness/sqrt(2),hhh+lever_thickness/2]);
      }
     }
     translate([0,-longwing,ls_z]) rotate([0,-90,0])
     finger_indent(d=lever_thickness-1,r=15);
    } // translate
    
    // pushfit bracket
    translate([0,0,filament_elevation])
    rotate([0,0,45]) translate([pulley_d/2,0,0])
    rotate([-90,0,0])
    translate([0,0,mount_d/sqrt(2)/2+mount_screw_d-gearbox_d/2/*TODO:*/])
    cylinder(r=min(body_h-filament_elevation,filament_elevation)/sin(60)-epsilon,h=10+gearbox_d/2/*TODO:*/,$fn=6);
   }//union (first child of difference)
   // protrusion
   translate([0,0,-1])
   cylinder(d=protrusion_d+protrusion_tolerance_h,h=protrusion_h+protrusion_tolerance_v+1,$fn=2*PI*protrusion_d);
   // mount screw holes
   for(zr=[0:90:359]) rotate([0,0,zr]) translate([mount_d/2,0,0]) {
    translate([0,0,mount_screw_l-mounthole_depth/2-layer_height-1])
    mirror([0,0,1])
    cylinder(d=mount_screw_d+mount_screw_d_tolerance,
             h=mount_screw_l-mounthole_depth/2-layer_height+1,
	     $fn=2*PI*mount_screw_d);
    translate([0,0,mount_screw_l-mounthole_depth/2])
    cylinder(d=mount_screwhead_d,h=body_h+1,$fn=2*PI*mount_screwhead_d);
   }//for
   // pushfit threads
   translate([0,0,filament_elevation])
   rotate([0,0,45]) translate([pulley_d/2,0,0])
   rotate([-90,0,0])
   translate([0,0,mount_d/sqrt(2)/2+mount_screw_d+epsilon])
   rotate([0,0,180]) {
    pushfit_thread(h=10);
    cylinder(d=filament_guide_d,h=gearbox_d,center=true,$fn=2*PI*filament_guide_d);
    translate([0,-filament_guide_d/2/sqrt(2),0])
    rotate([0,0,45])
    cube(size=[filament_guide_d/2,filament_guide_d/2,gearbox_d],center=true);
   }
   // pulley
   cylinder(d=pulley_d+pulley_clearance,h=body_h+1,$fn=2*PI*(pulley_d+pulley_clearance));
   // leverspace
   hull() for(x=[0,gearbox_d])
   rotate([0,0,45])
   translate([x,0,ls_z-ls_h/2])
   cylinder(d=idler_d+idler_clearance,h=ls_h,$fn=2*PI*idler_d);
   
   a=cos(45)*(pulley_d+idler_d)/2;
   b=mount_d/2-a;
   x=sqrt(pow(a,2)+pow(b,2));
   translate([mount_d/2,0,ls_z])
   intersection() {
    r = x+idler_d/2+1;/* TODO: */
    cylinder(r=r,h=ls_h,center=true);
    translate([-r-1,0,-1]) cube(size=[2*r+2,r+1,ls_h+2]);
   }
   
   rotate([0,0,-45])
   translate([0,0,ls_z-ls_h/2])
   cube(size=[gearbox_d,gearbox_d,lever_thickness+lever_v_clearance]);
   translate([0,0,ls_z-ls_h/2]) {
    translate([mount_screwhead_d/2,0,0])
    mirror([0,1,0])
    cube(size=[gearbox_d,gearbox_d/2+1,lever_thickness+lever_v_clearance]);
   }
   //translate([-mount_d/2,-longwing,filament_elevation])
   translate([mount_d/2,-longwing,filament_elevation])
   rotate([0,-90,0]) difference() {
    cylinder(d=spring_d+spring_d_clearance,h=spring_lc+spring_dl,$fn=PI*spring_d);
    translate([0,0,spring_lc+spring_dl]) sphere(d=spring_d*3/4,$fn=PI*spring_d);
   }
   //sphere(d=spring_d*3/4,$fn=PI*spring_d);
   *difference() {
    // spring support
    translate([0,-longwing,filament_elevation])
    sphere(d=spring_d*3/4,$fn=PI*spring_d);
   }
    
  }//difference

  intersection() {
   difference() {
    translate([0,0,ls_z-ls_h/2-epsilon])
    cylinder(d=gearbox_d,h=ls_h+2*epsilon,$fn=2*PI*gearbox_d);
    cylinder(d=pulley_d+pulley_clearance,h=body_h+1,$fn=2*PI*(pulley_d+pulley_clearance));
   }
   // supports
   // TODO: hardcoded stuff below…
   if(false) { // parallel
    for(y=[-gearbox_d:4:gearbox_d])
     translate([0,y-extrusion_width/2,0])
     cube(size=[gearbox_d,extrusion_width,body_h]);
   }else{ // radial
    for(zr=[-65:(65+50)/7:50])
     rotate([0,0,zr]) translate([0,-extrusion_width/2,0])
     cube(size=[gearbox_d,extrusion_width,body_h]);
   }
  }

 }//body module

 module knob() {
  ch = knob_indent_d/2;
  translate([0,0,body_h+epsilon]) {
   mirror([0,0,1]) translate([0,0,-epsilon]) {
    difference() {
     cylinder(d=pulley_d,h=knob_bore_l,$fn=pulley_d*PI*2);
     translate([0,0,-1]) difference() {
      cylinder(d=bore_d+knob_bore_d_tolerance,h=knob_bore_l+2);
      translate([-bore_d/2-1,bore_dd-bore_d/2+knob_bore_d_tolerance/2,-1])
      cube([bore_d+2,bore_d/2,knob_bore_l+4]);
     }
    }
   }
   difference() {
    union() {
     cylinder(d1=gearbox_d-2*ch,d2=gearbox_d,h=ch+epsilon,$fn=PI*gearbox_d*2);
     translate([0,0,ch])
     cylinder(d=gearbox_d,h=knob_h-2*ch+epsilon,$fn=PI*gearbox_d*2);
     translate([0,0,knob_h-ch])
     cylinder(d1=gearbox_d,d2=gearbox_d-2*ch,h=ch,$fn=PI*gearbox_d*2);
    }
    for(a=[0:360/knob_indents:359]) rotate([0,0,a])
     translate([0,gearbox_d/2,-1])
     cylinder(d=knob_indent_d,h=knob_h+2,$fn=knob_indent_d*PI*2);
   }
  }
 }//knob module
 
 mirrorleft()
 if(what=="lever") color("green",0.7) lever();
 else if(what=="body") color("yellow",0.7) body();
 else if(what=="knob") color("red",0.7) knob();
 else if(what=="both" || what=="*") {
  color("green",0.7) lever();
  color("yellow",0.7) body();
  color("red",0.7) knob();
 }
}

the_extruder(what="both",left=false);