The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Tag: Thing-O-Matic

Using and tweaking a Makerbot Thing-O-Matic 3D printer

  • HT GPS+Voice Case: Latch Bar

    This iteration of the case latch has slightly larger brass tubing on the ends, hand filed to match the case angle:

    Shaping case latch bar
    Shaping case latch bar

    It’s pretty much the same process described there and is why I set up that slitting saw arbor for the next time.

    The final result looks pretty good:

    HT-GPS Case - Latch plate detail
    HT-GPS Case – Latch plate detail

    Those tubing snippets really must be two different lengths: the bar slides to the right (in that picture) to release the case, so:

    • The short tube and the notch must fit into the space between the edge of the case and the release slot.
    • The long tube slides outward, with a mark to indicate when the notches align with the release slots.

    In principle, you could slide the bar until the shorter tube jams against the latch ramp on the radio, but this case (plus the end caps) turned out to be exactly as long as the distance available and is a rather snug press fit. The next version will be 0.75 mm shorter and should fit better, although snug is good in this situation.

  • Wouxun HT GPS+Voice Case: Colors!

    Rather than print another green case, the new, improved case has orange end caps:

    HT-GPS Case - End caps on build plate
    HT-GPS Case – End caps on build plate

    And a blue shell that’s a bit easier on the eye:

    HT-GPS Case - Shell on build platform
    HT-GPS Case – Shell on build platform

    Put ’em together and it certainly looks peppy, doesn’t it?

    HT-GPS Case - trial fit
    HT-GPS Case – trial fit

    That’s a trial fit with nothing inside, of course.

    Next step: circuitry!

  • CO2 Capsule Fins: Party Edition

    CO2 capsules with multicolored fins
    CO2 capsules with multicolored fins

    These emerged from some recent printing sessions, where they served to join two successive colors as I changed ABS filaments.

    Whenever I give a talk, these are the last tchotchkes to go. Maybe some festive party fins will help?

  • Harbor Freight Slitting Saw Arbor

    A three-pack of 100-tooth 2 inch cutoff saw blades followed me home from Harbor Freight a while ago. Although they’re intended for a craptastic HF tabletop saw, I thought they might come in handy on the Sherline for slicing lengths of brass tubing. The reviews for the saw indicate the blades are no good for steel, barely adequate for brass, and dandy for wood; they have nowhere near enough teeth for a screw cutoff blade.

    None of the arbors in my collection fit a blade with a 3/8 inch hole, so a bit of lathe work produced one while the 3D printer cranked out a GPS+audio case:

    Cutoff saw arbor in Sherline toolholder
    Cutoff saw arbor in Sherline toolholder

    The shaft is 3/8 inch drill rod and the collars are 3/4 inch drill rod, both of O1 oil-hardening steel that will remain forever unhardened, fitting into a Sherline endmill toolholder. I drilled-and-bored the collars to a slip fit on the shaft, then epoxied the rear one in place:

    img_2156 - Cutoff saw arbor - parts
    img_2156 – Cutoff saw arbor – parts

    I drilled a 0.6 inch deep blind hole in the shaft and tapped it 10-32 all the way down for a 1/2 inch SHCS. A bag of assorted 10-32 taps produced a bottoming tap that came in handy, but I put tapping in the same category as parallel parking: I’ll walk half a mile to not parallel park the van. Couldn’t avoid it this time.

    The flat on the shaft came from a bit of hand filing, which was easier than setting up the mill.

    The front collar’s undercut ensures just the rim contacts the blade. The photo shows the vanishingly thin layer of epoxy on the rear collar that mooshed out as I clamped the stack together:

    • Fixed (rear) collar
    • Waxed paper with a 3/8 inch hole punched in the middle
    • Cutoff blade
    • Split lockwasher for a bit of space
    • Loose (front) collar
    • Socket head cap screw

    After the epoxy cured, a pass through the lathe skimmed off that thin epoxy layer and trued up the fixed collar face to eliminate the last bit of wobble. The radial runout remains just enough so that one tooth tings before the others engage, but I’m not entirely convinced that’s due to the (minimal) shaft-to-blade clearance.

    In use, putting the split lockwasher between the loose collar and the SHCS provides a little clamping compliance.

    At some point, I’m sure this thing will come in handy…

  • Wouxun KG-UV3D GPS+Voice Interface: Improved Case

    This case has a few refinements beyond that one, but it’s recognizably a descendant. The main changes:

    • The HT cable port on the side has a nice polygonal roof to reduce overhang
    • The serial connector sits in a recess to allow a thicker top plate
    • Smaller opening for the LEDs; I’ll get a window in this one, fer shure, yeah
    • 4-40 screws hold the base plate on; setscrews may work and look better

    Looks like I’ll be using blue filament for this version, having just discovered the last of the weird colors in the bottom of the 5 gallon bucket serving as a storage bin.

    A view from the top:

    Solid Model - Oblique Exploded Top
    Solid Model – Oblique Exploded Top

    And from the base:

    Solid Model - Oblique Exploded Base
    Solid Model – Oblique Exploded Base

    The OpenSCAD source code:

    // Wouxun KB-UV3D Battery Pack Case
    // Ed Nisley KE4ZNU July 2012
    
    include </home/ed/Thing-O-Matic/lib/MCAD/units.scad>
    include </home/ed/Thing-O-Matic/Useful Sizes.scad>
    
    // Layout options
    
    Layout = "Show";
    					// Overall layout: Fit Show
    					// Printing plates: Build1 .. Buildn (see bottom!)
    					// Parts: TT3 Audio DSub Shell Base Top
    					// Shapes: RadioBase Contact
    					// Speaker-mic mount: PlugPlate
    
    ShowGap = 10;		// spacing between parts in Show layout
    
    //- Extrusion parameters must match reality!
    //  Print with +1 shells and 3 solid layers
    
    ThreadThick = 0.25;
    ThreadWidth = 2.0 * ThreadThick;
    
    HoleWindage = 0.2;
    
    function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);
    
    Protrusion = 0.1;			// make holes end cleanly
    
    //----------------------
    // Dimensions
    
    CaseOverallHeight = 31.5;				// from battery surface, must clear PCBs!
    CaseOverallWidth = 56;
    CaseOverallLength = 80.25;				// inside of base to end of compartment
    
    BatteryClearance = 1.5;					// contact seal height = air gap to compartment
    
    // Interface to radio battery contacts
    //	Length = shell length
    //		calculated after everything else, so as to fill the compartment
    
    ContactDia = 6.0;				// use rounded contact for simplicity
    ContactRecess = IntegerMultiple(0.75,ThreadThick);	// recess for contact plate
    ContactGapX = 10.5;				// X space between contacts
    Contact1Y = 52.5;				// offset from base to edge of contact
    Contact2Y = 56.5;
    ContactStudDia = Clear4_40;
    ContactStudHead = IntegerMultiple(Head4_40,ThreadWidth);
    ContactStudHeadThick = Head4_40Thick;
    
    PlateWidthMin = 53.0;
    PlateWidthMax = 54.5;
    PlateThick = IntegerMultiple(ContactRecess + ContactStudHeadThick,ThreadThick);
    PlateAngle = atan(PlateThick/(PlateWidthMax/2 - PlateWidthMin/2));
    
    echo("Battery plate thick: ",PlateThick);
    
    // Offsets from battery surface to PCB centerlines
    //	TT3 must be above HT back shell for DB9 clearance
    //	These must cooperate with the numbers in the case shell module
    
    TT3Offset = 17.5 + PlateThick;
    AudioOffset = 4.0 + PlateThick;
    
    // Plate interface to base alignment holes and notches
    
    BaseWidthInner = PlateWidthMin;
    BaseWidthOuter = CaseOverallWidth;
    BaseLength = CaseOverallHeight;					// perpendicular to battery surface
    BaseThick = IntegerMultiple(1.0,ThreadThick);	// minimum sheet thickness below teeth
    BaseWidthTaper = 5.0;							// ramp across entire width
    
    BaseOpeningMax = 43.0;
    BaseOpeningMin = 33.0;
    BaseOpeningY = 5.3;
    BaseOpeningDepth = IntegerMultiple(2.25,ThreadThick);
    
    BaseTotalThick = BaseThick + BaseOpeningDepth;
    echo("Base min thick: ",BaseThick," total: " ,BaseTotalThick);
    
    BaseTabWidth = 6.0;
    BaseTabThick = 2.0;
    BaseTabGap = 7.0;
    BaseTabOC = BaseTabWidth + BaseTabGap;
    BaseToothSection = 3*BaseTabWidth + 2*BaseTabGap;
    
    BaseToothBase = 5.8;
    BaseToothTip = 2.8;
    BaseToothThick = 2.0;
    BaseToothAngle = atan(BaseOpeningDepth/0.6);
    BaseToothOC = BaseTabOC;
    
    WedgeAngle = atan(BaseWidthTaper/((BaseWidthOuter - BaseWidthInner)/2));
    
    BaseEndLip = ThreadThick;			// should be 0.25 mm or so
    BaseEndWidth = (PlateWidthMin - 3*BaseToothBase - 2*BaseToothTip)/2;
    BaseEndAngle = atan((BaseOpeningDepth - BaseEndLip)/BaseOpeningY);
    
    SwitchBody = [8.6,3.7,3.3];			// mode switch
    
    // Plate interface to HT battery latch, cables, and connectors
    
    TopThick = IntegerMultiple(5.5,ThreadThick);	// plate thickness for stiffness behind latch bar
    echo("Top plate thick: ",TopThick);
    
    DB9Recess = TopThick - 4.0;			// recess to max TT3 PCB clearance behind DB9 plate
    
    TabEngageLength = 1.6;				// tab engaging surface length
    TabWidth = 3.0;						//  ... width
    TabEngageHeight = 4.5;				//  ... above battery compartment floor
    TabHeight = 7.5;					// tab ramp top above battery compartment floor
    TabOC = 40.0;
    
    LatchBarWidth = 3.4;				// sliding latch mechanism (brass L stock)
    LatchBarDepth = 3.4;
    LatchBarThick = 0.35;
    
    echo(" ... minimum: ",TopThick - LatchBarDepth);
    
    SplitOffset = TT3Offset - 3.5;
    
    TopBevel = 1.0;						// bevel at top of battery compartment
    TopBevelAngle = 45;
    
    PinOffsetWidth = 2.5;				// choose to center in sides of case shell
    PinOffsetHeight = 13.5;				// above baseplate bottom
    PinDepth = 7.0;						// into case shell
    PinDia = 1.2;
    
    ShellLength = CaseOverallLength - BaseThick - TopThick;
    
    echo("Shell length: ",ShellLength);
    
    // Speaker-mic plug plate
    
    PlugBaseThick = 2.5;				// recess depth
    PlugFillThick = 3.0;				// outer plate thickness
    
    //----------------------
    // 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);
    }
    
    module ShowPegGrid(Space = 10.0,Size = 1.0) {
    
    Range = floor(50 / Space);
    
    	for (x=[-Range:Range])
    	  for (y=[-Range:Range])
    		translate([x*Space,y*Space,Size/2])
    		  %cube(Size,center=true);
    
    }
    
    //-------------------
    // Component parts
    
    //-----
    // TinyTrak3+ PCB and component envelope
    //	Some dimensions should feed into the case shell, but don't
    
    module TinyTrak3(Length = 1.0) {
    
    PCBThick = 1.6;
    PCBWide = 36.5;
    TopHigh = 9.5;
    TopWide = PCBWide - 1.5;
    BotHigh = 2.5;
    BotWide = 35.0;
    
    PCBx = PCBWide/2;
    PCBy = (PCBThick + HoleWindage)/2;
    URx = TopWide/2;
    URy = PCBy + TopHigh;
    LRx = BotWide/2;
    LRy = PCBy + BotHigh;
    
    linear_extrude(height=Length,center=false,convexity=2) {
    	polygon(points=[[URx,URy],[URx,PCBy],[PCBx,PCBy],[PCBx,-PCBy],[LRx,-PCBy],[LRx,-LRy],
    					[-LRx,-LRy],[-LRx,-PCBy],[-PCBx,-PCBy],[-PCBx,PCBy],[-URx,PCBy],[-URx,URy]
    				   ]);
    }
    }
    
    //-----
    // Interface PCB and component envelope
    //	Some dimensions should feed into the case shell, but don't
    
    module AudioInterface(Length = 1.0) {
    
    PCBThick = 2.0;
    PCBWide = 49.5;
    TopHigh = 9.0 + Protrusion;
    TopWide = 46.0;
    BotHigh = 3.0;
    BotWide = 44.0;
    
    PCBx = PCBWide/2;
    PCBy = (PCBThick + HoleWindage)/2;
    URx = TopWide/2;
    URy = PCBy + TopHigh;
    LRx = BotWide/2;
    LRy = PCBy + BotHigh;
    
    linear_extrude(height=Length,center=false,convexity=2) {
    	polygon(points=[[URx,URy],[URx,PCBy],[PCBx,PCBy],[PCBx,-PCBy],[LRx,-PCBy],[LRx,-LRy],
    					[-LRx,-LRy],[-LRx,-PCBy],[-PCBx,-PCBy],[-PCBx,PCBy],[-URx,PCBy],[-URx,URy]
    				   ]);
    }
    }
    
    //-----
    // DB-9 (DE-9) panel opening
    // http://www.interfacebus.com/Connector_D-Sub_Mechanical_Dimensions.html
    //  DB-9 shell mounts on outside surface of case
    // This is for the solder terminal side
    
    module DSubMin9(Length = 1.0) {
    
    Holex = 0.984/2 * inch;
    HoleDia = Tap4_40;
    
    URx = 0.769/2 * inch;
    URy = 0.432/2 * inch;
    
    	linear_extrude(height=Length,center=false,convexity=3) {
    	  polygon(points=[[URx,URy],[URx,-URy],[-URx,-URy],[-URx,URy]]);
    	  for (x = [-1,1]) {
    		translate([x*Holex,0,0])
    		  rotate(45) circle(r=(HoleDia + HoleWindage)/2,$fn=4);
    	  }
    	}
    
    }
    
    //-----
    // Central case shape
    //	This *should* depend directly on the circuit board sizes, but doesn't
    //	The "Offset" parameters attempt to bottle up all the board sizes
    //	Support in LED window must be hand-fit to work correctly... and isn't needed!
    
    module CaseShell(Length=(ShellLength),Holes="true") {
    
    // Polygon coordinates are in XY plane
    
    URx = 40.0/2;
    URy = CaseOverallHeight;
    
    MRx = CaseOverallWidth/2;
    MRy = 15.0;
    
    LRx = CaseOverallWidth/2;
    LRy = (LRx - PlateWidthMin/2)*tan(PlateAngle);
    
    BRx = PlateWidthMax/2;
    BRy = PlateThick - 0*Protrusion;
    
    PRx = PlateWidthMin/2;				// combined battery plate
    PRy = 0;
    
    ScrewOffset = 20.0;					// from top end of case
    
    LEDWindow = [26.0,5.0,6];			// with case aligned vertically
    LEDOffset = [15,URy,(Length + TopThick - 25.0)];
    
    TrimPot1 = [-14,TT3Offset,(Length + TopThick - 30)];
    TrimPot2 = [-14,TT3Offset,(Length + TopThick - 37.5)];
    
    HTCableDia = 3.5;
    HTCableOffset = AudioOffset + HTCableDia/2 + 1.0;
    
    rotate([90,0,180])
    	union() {
    	  difference() {
    
    		  linear_extrude(height=Length,center=false,convexity=5)
    			polygon(points=[[URx,URy],[MRx,MRy],[LRx,LRy],[BRx,BRy],[PRx,PRy],
    							[-PRx,PRy],[-BRx,BRy],[-LRx,LRy],[-MRx,MRy],[-URx,URy]]);
    
    		if (Holes) {
    		  translate([0,AudioOffset,-Protrusion])
    			AudioInterface(Length + 2*Protrusion);
    
    		  translate([0,TT3Offset,-Protrusion])
    			TinyTrak3(Length + 2*Protrusion);
    
    		  for (y = [TT3Offset,AudioOffset])
    			translate([-CaseOverallWidth,y,(Length - ScrewOffset)])
    			  rotate([0,90,0])
    				rotate(0)					// Z rotation puts point upward for printing
    				PolyCyl(Tap4_40,CaseOverallWidth);
    
    		  translate(LEDOffset)
    			rotate([90,90,0])
    			  translate([-LEDWindow[0]/2,-LEDWindow[1]/2,-Protrusion])
    			  cube(LEDWindow,center=false);
    
    		  for (p = [TrimPot1,TrimPot2])
    			translate(p)
    			  rotate([-90,90,0])				// Y rotation puts point upward for printing
    				PolyCyl(3.0,URy);
    
    		  for (x=[-1,1]) {
    			translate([x*(CaseOverallWidth/2 - PinOffsetWidth),
    					  PinOffsetHeight,
    					  (Length - PinDepth)])
    			  rotate(45)						// align hole sides with case sides
    				  PolyCyl(PinDia,2*TopThick);
    			translate([x*(CaseOverallWidth/2 - PinOffsetWidth),
    					  PinOffsetHeight,
    					  -PlateThick])
    			  rotate(45)						// align hole sides with case sides
    				  PolyCyl(PinDia,(PlateThick + PinDepth));
    		  }
    
    		  for (x=[-1,1])						// setscrews to secure base plate
    			translate([x*(CaseOverallWidth/2 - 3*Tap4_40),
    					  TT3Offset,-Protrusion])
    			  rotate(360/(5*4))
    				PolyCyl(Tap4_40,2*TopThick);
    
    		  translate([-(ContactGapX/2 + ContactDia/2),0,(Contact1Y + ContactDia/2)])
    			rotate([90,0,0])
    			  Contact();
    		  translate([+(ContactGapX/2 + ContactDia/2),0,(Contact2Y + ContactDia/2)])
    			rotate([90,0,0])
    			  Contact();
    
    		  translate([CaseOverallWidth/2,HTCableOffset,(Length - HTCableDia/4)])
    			rotate([0,90,0])
    			  cube([(HTCableDia/2 + Protrusion),HTCableDia,CaseOverallWidth],center=true);
    		  translate([0,HTCableOffset,(Length - HTCableDia/2)])
    			rotate([0,90,0])
    			  cylinder(r=(1/cos(30))*HTCableDia/2,h=CaseOverallWidth,$fn=6);
    		}
    	  }
    
    if (false)
    	  if (Holes)
    		translate(LEDOffset)						// support plug in LED window
    		  rotate([90,90,0])
    			translate([-0.95*LEDWindow[0]/2,-0.80*LEDWindow[1]/2,ThreadWidth/2])
    			  cube([0.95*LEDWindow[0],0.80*LEDWindow[1],2*ThreadWidth],center=false);
    
    	}
    
    }
    
    //-----
    // Battery contact recess
    //  This gets subtracted from the bottom plate in two places
    // 	Align points to print upward
    
    module Contact() {
    
    if (true)
    union() {													// vertical printing with case
    	translate([0,0,-(ContactRecess + Protrusion)/2])
    	  PolyCyl(ContactDia,(ContactRecess + Protrusion),8);
    	translate([0,0,-(PlateThick + Protrusion)])
    	  rotate(60/2)
    	  PolyCyl(ContactStudDia,PlateThick,6);
    	translate([0,0,-(ContactRecess + ContactStudHeadThick/3)])
    	  PolyCyl(ContactStudHead,ContactStudHeadThick,8);				// allow for solder blob
    }
    else
    union() {												// horizontal printing alone
    	translate([0,0,-(ContactRecess - Protrusion)/2])
    	  PolyCyl(ContactDia,(ContactRecess + Protrusion),8);
    	translate([0,0,-(PlateThick + Protrusion)])
    	  PolyCyl(ContactStudDia,(PlateThick + 2*Protrusion));
    	translate([0,0,-(ContactRecess + ContactStudHeadThick/3)])
    	  PolyCyl(ContactStudHead,ContactStudHeadThick,8);				// allow for solder blob
    }
    
    }
    
    //-----
    // Radio bottom locating feature
    //  This polygon gets subtracted from the battery pack base
    
    module RadioBase() {
    
    linear_extrude(height=(BaseOpeningDepth + Protrusion),center=false,convexity=5)
    polygon(points=[
    			[-BaseOpeningMax/2,-Protrusion],
    
    			[-BaseOpeningMin/2,BaseOpeningY],
    			[-(BaseToothOC/2 + BaseToothBase/2),BaseOpeningY],
    
    			[-(BaseToothOC/2 + BaseToothTip/2),(BaseOpeningY - BaseToothThick)],
    			[-(BaseToothOC/2 - BaseToothTip/2),(BaseOpeningY - BaseToothThick)],
    			[-(BaseToothOC/2 - BaseToothBase/2),BaseOpeningY],
    
    			[ (BaseToothOC/2 - BaseToothBase/2),BaseOpeningY],
    			[ (BaseToothOC/2 - BaseToothTip/2),(BaseOpeningY - BaseToothThick)],
    			[ (BaseToothOC/2 + BaseToothTip/2),(BaseOpeningY - BaseToothThick)],
    			[ (BaseToothOC/2 + BaseToothBase/2),BaseOpeningY],
    			[ BaseOpeningMin/2,BaseOpeningY],
    
    			[ BaseOpeningMax/2,-Protrusion],
    
    			[ (BaseTabOC + BaseTabWidth/2),-Protrusion],
    			[ (BaseTabOC + BaseTabWidth/2),BaseTabThick],
    			[ (BaseTabOC - BaseTabWidth/2),BaseTabThick],
    			[ (BaseTabOC - BaseTabWidth/2),-Protrusion],
    
    			[ BaseTabWidth/2,-Protrusion],
    			[ BaseTabWidth/2,BaseTabThick],
    			[-BaseTabWidth/2,BaseTabThick],
    			[-BaseTabWidth/2,-Protrusion],
    
    			[-(BaseTabOC + BaseTabWidth/2),-Protrusion],
    			[-(BaseTabOC + BaseTabWidth/2),BaseTabThick],
    			[-(BaseTabOC - BaseTabWidth/2),BaseTabThick],
    			[-(BaseTabOC - BaseTabWidth/2),-Protrusion],
    		  ],
    		  convexity=5
    );
    }
    
    //-----
    // Battery pack base
    
    module Base() {
    
    difference() {
    
    	rotate([-90,180,0])						// main case shape
    	  CaseShell(BaseTotalThick,false);
    
    	translate([0,0,BaseThick])				// radio base interface
    	  RadioBase();
    
    	translate([0,0,BaseThick])				// tooth bevel
    	  rotate([(-90 + BaseToothAngle),0,0])
    		translate([0,-0.5,0])
    		  cube([(BaseToothSection + 2*Protrusion),1.0,10],center=true);
    
    	translate([-BaseWidthOuter,				// surface slope
    			  -(BaseThick + BaseEndLip)/tan(BaseEndAngle),0])
    	  rotate([BaseEndAngle,0,0])
    		difference() {
    		  cube([2*BaseWidthOuter,3*BaseOpeningY,BaseOpeningDepth],center=false);
    		  translate([(BaseWidthOuter - (BaseToothSection + 2*Protrusion)/2),0,0])
    			cube([(BaseToothSection + 2*Protrusion),1.2*BaseOpeningY,BaseOpeningDepth],center=false);
    		}
    
    	for (x=[-1,1])							// alignment pin holes
    	  translate([x*(CaseOverallWidth/2 - PinOffsetWidth),PinOffsetHeight,-Protrusion])
    		rotate(45)							// align hole side with plate side
    		  PolyCyl(PinDia,2*TopThick);
    
    	for (x=[-1,1])							// mounting setscews
    	  translate([x*(CaseOverallWidth/2 - 3*Tap4_40),
    				TT3Offset,-Protrusion])
    		rotate(-360/(-5*4))
    		  PolyCyl(Tap4_40,2*TopThick);
    
    	translate([(-SwitchBody[0]/2),TT3Offset,-SwitchBody[2]/2])	// mode switch
    	  scale([1,1,2])
    		cube(SwitchBody);
    
    }
    }
    
    //-----
    // Top plate with latch
    //	Split around TinyTrak3 serial connector
    //	 ... which must be at the same height as in the shell!
    //	The cable hole sizes & locations are entirely ad-hoc
    
    module TopPlate() {
    
    Cable1Dia = 5.0;
    Cable2Dia = 5.0;
    CableHoleLength = TopThick + 2*Protrusion;
    CableHoleZ = -Protrusion;
    
    DB9Plate = [32.0,13.5,1.25];					// plate surrounding connector body
    
    difference() {
    
    	rotate([-90,180,180])
    	  CaseShell(TopThick,false);
    
    	translate([0,-TT3Offset,-Protrusion])
    	  DSubMin9(TopThick + 2*Protrusion);
    
    	translate([0,-TT3Offset,(TopThick - DB9Plate[2]/2)])
    	  cube([DB9Plate[0],DB9Plate[1],(DB9Plate[2] + Protrusion)],center=true);
    
    	translate([-CaseOverallWidth,-SplitOffset,-2*Protrusion])		// split the plate
    	  cube([2*CaseOverallWidth,4*Protrusion,(TopThick + 2*Protrusion)]);
    
    	translate([0,0,(TopThick - TopBevel)])
    	  rotate([-TopBevelAngle,0,0])
    		translate([-CaseOverallWidth,-TopThick,0])
    		  cube([2*CaseOverallWidth,2*TopThick,2*TopThick],center=false);
    
    	for (x=[-1,1])
    	  translate([(x*TabOC/2),
    				(-TabHeight/2 + Protrusion),
    				(TopThick - TabEngageLength/2 + Protrusion/2)])
    		rotate([90,0,0])
    		  cube([TabWidth,
    				(TabEngageLength + Protrusion),
    				(TabHeight + Protrusion)],center=true);
    
    	translate([-CaseOverallWidth,
    			  -(TabEngageHeight + LatchBarWidth - BatteryClearance),
    			  (TopThick - LatchBarDepth)])
    	  cube([2*CaseOverallWidth,(LatchBarWidth + LatchBarThick),(LatchBarDepth + Protrusion)]);
    
    	for (x=[-1,1])
    	  translate([(x*CaseOverallWidth/4),
    				-(TabEngageHeight + LatchBarWidth + Clear2_56/2 - BatteryClearance + Protrusion),
    				0]) {
    		translate([0,0,-Protrusion])
    		  rotate(45)						// align sides with slot
    			PolyCyl(Tap2_56,(TopThick + 2*Protrusion));
    		translate([0,0,(TopThick - LatchBarDepth)])
    		  rotate(60)						// align sides with slot
    			PolyCyl((Head2_56 + Protrusion),TopThick,6);		// extra extra clearance
    	  }
    
    	for (x=[-1,1])
    	  translate([x*(CaseOverallWidth/2 - PinOffsetWidth),-PinOffsetHeight,-Protrusion])
    		rotate(45)						// align hole side with plate side
    		  PolyCyl(PinDia,2*TopThick);
    
    	for (x=[-1,1])						// coincidentally line up with latch tabs
    	  translate([(x*TabOC/2),-(SplitOffset - 3.0),-Protrusion])
    		scale([1,1.7,1])
    		  PolyCyl(Cable1Dia,CableHoleLength,6);
    }
    
    }
    
    //-----
    // Speaker-Mic plug mounting plate
    
    module PlugPlate() {
    
    JackOC = 11.20;						// 14.25 OD - (3.58 + 2.58)/2
    
    JackScrewDia = 4.6;
    JackScrewOffsetX = 1.00;
    JackScrewOffsetY = 5.25;			//  mounting screw to edge of lower recess
    
    PlugBaseWidth = 9.25;				// lower section of plate
    PlugBaseLength = 22.0;
    PlugBaseRadius = 1.75;
    
    Plug3Offset = 5.25;					// edge of base recess to 3.5 mm jack
    
    Plug2BezelDia = 7.1;				// 2.5 mm plug
    Plug2BezelThick = 1.04;
    Plug2ScrewDia = 6.0;
    Plug3ScrewLength = 3.0;
    
    Plug3BezelDia = 8.13;				// 3.5 mm plug
    Plug3BezelThick = 1.6;
    Plug3ScrewDia = 7.95;
    Plug3ScrewLength = 4.0;
    
    PlugFillOffsetX = JackScrewOffsetX - 0.5;		// base recess CL to fill CL
    PlugFillOffsetY = -10.5;				//  ... to edge of fill plate
    PlugFillWidth = 11.0;
    PlugFillLength = 34.00;
    PlugFillRadius1 = 1.5;
    PlugFillRadius2 = 4.5;
    
    PlugFillOffsetYTotal = 0;
    
    BaseX = PlugBaseWidth/2 - PlugBaseRadius;
    BaseY = PlugBaseLength/2 - PlugBaseRadius;
    
    difference() {
    	union() {
    	  linear_extrude(height=PlugBaseThick,center=false,convexity=3)
    		hull() {
    		  translate([-BaseX,-BaseY,0])
    			circle(r=PlugBaseRadius,$fn=8);
    		  translate([-BaseX, BaseY,0])
    			circle(r=PlugBaseRadius,$fn=8);
    		  translate([ BaseX, BaseY,0])
    			circle(r=PlugBaseRadius,$fn=8);
    		  translate([ BaseX,-BaseY,0])
    			circle(r=PlugBaseRadius,$fn=8);
    		}
    
    	  translate([PlugFillOffsetX,
    				(PlugFillLength/2 - PlugBaseLength/2 + PlugFillOffsetY),
    				PlugBaseThick])
    		linear_extrude(height=PlugFillThick,center=false,convexity=5)
    		  hull() {
    			translate([0,-(PlugFillLength/2 - PlugFillRadius2),0])
    			  circle(r=PlugFillRadius2,$fn=10);
    			translate([-(PlugFillWidth/2 - PlugFillRadius1),-PlugBaseLength/2,0])
    			  circle(r=PlugFillRadius1,$fn=8);
    			translate([-(PlugFillWidth/2 - PlugFillRadius1),
    					  (PlugFillLength/2 - PlugFillRadius1),0])
    			  circle(r=PlugFillRadius1,$fn=8);
    			translate([(PlugFillWidth/2 - PlugFillRadius1),
    					  (PlugFillLength/2 - PlugFillRadius1),0])
    			  circle(r=PlugFillRadius1,$fn=8);
    			translate([(PlugFillWidth/2 - PlugFillRadius1),-PlugBaseLength/2,0])
    			  circle(r=PlugFillRadius1,$fn=8);
    		  }
    	}
    
    	translate([0,-JackOC/2,-Protrusion])
    	  rotate(360/16) {
    		PolyCyl(Plug3BezelDia,(Plug3BezelThick + Protrusion),8);
    		PolyCyl(Plug3ScrewDia,(PlugBaseThick + PlugFillThick + 2*Protrusion),8);
    	  }
    
    	translate([0,+JackOC/2,-Protrusion])
    	  rotate(360/16) {
    		PolyCyl(Plug2BezelDia,(Plug2BezelThick + Protrusion),8);
    		PolyCyl(Plug2ScrewDia,(PlugBaseThick + PlugFillThick + 2*Protrusion),8);
    	  }
    
    	translate([JackScrewOffsetX,-(PlugBaseLength/2 + JackScrewOffsetY),0])
    	  PolyCyl(JackScrewDia,(PlugBaseThick + PlugFillThick + Protrusion));
    }
    
    }
    
    //-------------------
    // Build things...
    
    ShowPegGrid();
    
    if (Layout == "TT3")
    TinyTrak3();
    
    if (Layout == "Audio")
    AudioInterface();
    
    if (Layout == "DSub")
    DSubMin9();
    
    if (Layout == "Shell")
    CaseShell(CaseOverallLength);
    
    if (Layout == "Top")
    TopPlate();
    
    if (Layout == "Base")
    Base();
    
    if (Layout == "RadioBase")
    RadioBase();
    
    if (Layout == "PlugPlate")
    PlugPlate();
    
    if (Layout == "Contact")
    rotate([180,0,0])
    	Contact();
    
    if (Layout == "Show" || Layout == "Fit") {
    
    translate([0,-ShellLength/2,0]) {
    
    	translate([0,(Layout == "Show")?-ShowGap:0,0])
    	  rotate([90,0,0])
    		color("SandyBrown") Base();
    
    	translate([0,0,0])
    	    color("LightGreen") render() CaseShell();
    
    	translate([-(CaseOverallWidth/2 + 10),50,CaseOverallHeight/2])
    	  rotate([0,-90,0])
    		color("Gold") PlugPlate();
    
    	translate([0,((Layout == "Show")?(ShellLength + ShowGap):ShellLength),0])
    	  rotate([-90,0,0])
    		color("BurlyWood") TopPlate();
    }
    }
    
    if (Layout == "Build1") {
    
    translate([5 + CaseOverallHeight,0,0])
    	rotate([0,0,90])
    	  Base();
    
    translate([-(5 + CaseOverallHeight),0,0])
    	rotate(90)
    	  TopPlate();
    
    }
    
    if (Layout == "Build2") {
    
    translate([0,-CaseOverallHeight/2,ShellLength])
    	rotate([-90,0,0])
    		CaseShell();
    
    }
    
    if (Layout == "Build3") {
    
    translate([0,0,(PlugBaseThick + PlugFillThick)])
    	rotate([180,0,0])
    	  PlugPlate();
    
    }
    
  • Fundamental 3D Printing Patents

    DIY 3D printing seems surrounded by Good Ideas that don’t happen, which led me to look up some of the early patents in the field. As nearly as I can tell, any bright idea one might have has already been patented; although you can usually get away with tinkering it up in your basement (because you’re not worth enough to interest the patent holder’s attorneys), anything beyond that will darken your skies with lawsuits.

    The granddaddy of all 3D extrusion machines seems to be US5121329 (Crump → Stratasys 1992-06-09): Apparatus and method for creating three-dimensional objects

    Exploring the patents referencing that one as a foundation should keep you busy for a while; the PDF has clicky links.

    Some fine tuning on the theme:

    US6085957 (Zinniel/Batchelder → Stratasys): Volumetric feed control for flexible filament

    US5303141 (Batchelder/et al → IBM): Model generation system having closed-loop extrusion nozzle positioning

    Congealing 3D objects in a vat of goo probably starts with 4575330 (Hull → MVP 1986-03-11): Apparatus for production of three-dimensional objects by stereolithography

    Remember: I’m not a patent attorney and my opinion is worthless…

    US5121329 - Figure 1
    US5121329 – Figure 1
  • Wouxun KG-UV3D GPS Interface: PCB Component Envelopes

    This doodle just emerged from the heap:

    TT3 and Interface PCB keepout dimensions
    TT3 and Interface PCB keepout dimensions

    It gives the envelope dimensions for the two PCBs in the quasi-extruded GPS interface case:

    HT-GPS Case - Trial fit - rear view
    HT-GPS Case – Trial fit – rear view

    The overall idea was to subtract the envelopes from the interior of the solid case and print the shell:

    HT-GPS Adapter Case - end view
    HT-GPS Adapter Case – end view

    Surprisingly, after minimal cleanout, the PCBs pretty much just slid into place and the setscrews locked them down.

    Now I can throw out that scrap of paper…

    The OpenSCAD source has the gory details; the actual dimensions don’t quite match the doodle, but that’s in the nature of fine tuning.