OpenSCAD Source Code: Chip-on-board LED Retrofit for a Cheap Desk Lamp

Chip On Board Heatsink Mount.scad

// Chip-on-board LED light heatsink mount for desk lamp
// Ed Nisley KE4ZNU December 2015

Layout = "Show";						// Show Build 

//- Extrusion parameters must match reality!

ThreadThick = 0.25;
ThreadWidth = 0.40;

HoleWindage = 0.2;

Protrusion = 0.1;			// make holes end cleanly

inch = 25.4;

function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);

//----------------------
// Dimensions

ID = 0;											// for round things
OD = 1;
LENGTH = 2;

Gooseneck = [3.0,5.0,15.0];						// anchor for end of gooseneck

COB = [25.0,23.0,2.5];							// Chip-on-board LED module

Heatsink = [35.5,31.5,4.0];						// height is solid base bottom
HSWire = [23.0,28.0,53.3];						// anchor width OC, width OAL, length OC
HSWireDia = 1.4;

HSLip = 1.0;									// width of lip under heatsink

BaseMargin = 2*2*ThreadWidth;
BaseRadius = Gooseneck[OD];						// 2 x gooseneck = enough anchor, sets slab thickness
BaseSides = 2*4;
Base = [(Gooseneck[LENGTH] + Gooseneck[OD] + Heatsink[0] + 2*BaseRadius + BaseMargin),
		(Heatsink[1] + 2*BaseRadius + 2*BaseMargin),
		2*BaseRadius];


//----------------------
// Useful routines

module PolyCyl(Dia,Height,ForceSides=0) {			// based on nophead's polyholes

  Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2);

  FixDia = Dia / cos(180/Sides);

  cylinder(r=(FixDia + HoleWindage)/2,
		h=Height,
	$fn=Sides);
}

//-- Lamp heatsink mount

module Lamp() {
	
		difference() {
			translate([(Base[0]/2 - BaseRadius - Gooseneck[LENGTH]),0,0])
				hull()
					for (i=[-1,1], j=[-1,1])
						translate([i*(Base[0]/2 - BaseRadius),j*(Base[1]/2 - BaseRadius),Base[2]/2])
							sphere(r=BaseRadius/cos(180/BaseSides),$fn=BaseSides);
								
			translate([(Heatsink[0]/2 + Gooseneck[OD]),0,Heatsink[2] + COB[2]])				// main heatsink recess
				scale([1,1,2])
					cube((Heatsink + [HoleWindage,HoleWindage,0.0]),center=true);
					
			translate([(Heatsink[0]/2 + Gooseneck[OD]),0,Heatsink[2] - Protrusion])			// lower lip to shade lamp module
				scale([1,1,2])
					cube(Heatsink - [2*HSLip,2*HSLip,0],center=true);
					
			translate([0,0,Base[2]/2])							// goooseneck insertion
				rotate([0,-90,0]) rotate(180/8)
					PolyCyl(Gooseneck[OD],Base[0],8);

			translate([0,0,Base[2]/2 + Gooseneck[ID]/2])		// wire exit
				rotate([180,0,0])
					PolyCyl(Gooseneck[ID],Base[2],6);

			translate([Gooseneck[OD],0,(COB[2] - Protrusion)/2])		// wire slot
				rotate([180,0,0])
					cube([2*Gooseneck[OD],Gooseneck[ID],(COB[2] + Protrusion)],center=true);

		}
		
}

//----------------------
// Build it

if (Layout == "Show") {
	Lamp();
}

if (Layout == "Build") {
	
}

More detail on my blog at http://wp.me/poZKh-5vy