Tag: M2

Using and tweaking a Makergear M2 3D printer

Astable Multivibrator: Dressed-up LED Spider

Adding a bit of trim to the bottom of the LED spider makes it look better and helps keep the strut wires in place:

Astable Multivibrator – Alkaline – Radome trim

It’s obviously impossible to build like that, so it’s split across the middle of the strut:

Astable Multivibrator – Alkaline – Radome trim

Glue it together with black adhesive and a couple of clamps:

LED Spider – glue clamping

The aluminum fixtures (jigs?) are epoxied around snippets of strut wire aligning the spider parts:

LED Spider – gluing fixture

Those grossly oversized holes came pre-drilled in an otherwise suitable aluminum rod from the Little Tray o’ Cutoffs. I faced off the ends, chopped the rod in two, recessed the new ends, and declared victory. Might need better ones at some point, but they’ll do for now.

Next step: wire up an astable with a yellow LED to go with the green and blue boosted LEDs.

2020-11-26
Kenmore Progressive Vacuum Cleaner vs. Dust Brush Adapters

Contemporary vacuum cleaner dust brush heads have bristles in some combination of [long | short] with [flexy | stiff]. The long + flexy combination results in the bristles jamming the inlet and the short + stiff combo seems unsuited for complex surfaces. Shaking the Amazonian dice brought a different combination:

Vacuum cleaner dust brush assortment – with adapters

That’s the new one on the bottom and, contrary to what you might think from the picture, it is not identical to the one just above it.

In particular, the black plastic housing came from a different mold (the seam lines are now top-and-bottom) and required a new adapter for the Kenmore Progressive vacuum cleaner’s complicated wand / hose inlet, with a 3/4 inch PVC pipe reinforcement inside.

Early reports indicate it works fine, so I’ll declare a temporary victory in the war on entropy.

I’m still using the same OpenSCAD source code with minute tweaks to suit the as-measured tapers.

2020-10-04

Raspberry Pi HQ Camera Mount

As far as I can tell, Raspberry Pi cases are a solved problem, so 3D printing an intricate widget to stick a Pi on the back of an HQ camera seems unnecessary unless you really, really like solid modeling, which, admittedly, can be a thing. All you really need is a simple adapter between the camera PCB and the case of your choice:

HQ Camera Backplate - OpenSCAD model — HQ Camera Backplate – OpenSCAD model

A quartet of 6 mm M2.5 nylon spacers mount the adapter to the camera PCB:

RPi HQ Camera - nylon standoffs — RPi HQ Camera – nylon standoffs

The plate has recesses to put the screw heads below the surface. I used nylon screws, but it doesn’t really matter.

The case has all the right openings, slots in the bottom for a pair of screws, and costs six bucks. A pair of M3 brass inserts epoxied into the plate capture the screws:

RPi HQ Camera - case adapter plate - screws — RPi HQ Camera – case adapter plate – screws

Thick washers punched from an old credit card go under the screws to compensate for the case’s silicone bump feet. I suppose Doing the Right Thing would involve 3D printed spacers matching the cross-shaped case cutouts.

Not everyone agrees with my choice of retina-burn orange PETG:

RPi HQ Camera - 16 mm lens - case adapter plate — RPi HQ Camera – 16 mm lens – case adapter plate

Yes, that’s a C-mount TV lens lurking in the background, about which more later.

The OpenSCAD source code as a GitHub Gist:

	// Raspberry Pi HQ Camera Backplate
	// Ed Nisley KE4ZNU 2020-09

	//– Extrusion parameters

	/* [Hidden] */

	ThreadThick = 0.25;
	ThreadWidth = 0.40;

	HoleWindage = 0.2;

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

	Protrusion = 0.1; // make holes end cleanly

	inch = 25.4;

	ID = 0;
	OD = 1;
	LENGTH = 2;

	//- Basic dimensions

	CamPCB = [39.0,39.0,1.5]; // Overall PCB size, plus a bit
	CornerRound = 3.0; // … has rounded corners

	CamScrewOC = [30.0,30.0,0]; // … mounting screw layout
	CamScrew = [2.5,5.0,2.2]; // … LENGTH = head thickness

	Standoff = [2.5,5.5,6.0]; // nylon standoffs

	Insert = [3.0,4.0,4.0];

	WallThick = IntegerMultiple(2.0,ThreadWidth);
	PlateThick = Insert[LENGTH];

	CamBox = [CamPCB.x + 2*WallThick,
	CamPCB.y + 2*WallThick,
	Standoff.z + PlateThick + CamPCB.z + 1.0];

	PiPlate = [90.0,60.0,PlateThick];
	PiPlateOffset = [0.0,(PiPlate.y – CamBox.y)/2,0];

	PiSlotOC = [0.0,40.0];
	PiSlotOffset = [3.5,3.5];

	NumSides = 234;

	TextDepth = 2*ThreadThick;

	//———————-
	// 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);
	}


	//———————-
	// Build it

	difference() {

	union() {
	hull() // camera enclosure
	for (i=[-1,1], j=[-1,1])
	translate([i(CamBox.x/2 – CornerRound),j(CamBox.y/2 – CornerRound),0])
	cylinder(r=CornerRound,h=CamBox.z,$fn=NumSides);
	translate(PiPlateOffset)
	hull()
	for (i=[-1,1], j=[-1,1]) // Pi case plate
	translate([i(PiPlate.x/2 – CornerRound),j(PiPlate.y/2 – CornerRound),0])
	cylinder(r=CornerRound,h=PiPlate.z,$fn=NumSides);
	}

	hull() // camera PCB space
	for (i=[-1,1], j=[-1,1])
	translate([i(CamPCB.x/2 – CornerRound),j(CamPCB.y/2 – CornerRound),PlateThick])
	cylinder(r=CornerRound,h=CamBox.z,$fn=NumSides);

	translate([0,-CamBox.y/2,PlateThick + CamBox.z/2])
	cube([CamScrewOC.x – Standoff[OD],CamBox.y,CamBox.z],center=true);

	for (i=[-1,1], j=[-1,1]) // camera screws with head recesses
	translate([iCamScrewOC.x/2,jCamScrewOC.y/2,-Protrusion]) {
	PolyCyl(CamScrew[ID],2*CamBox.z,6);
	PolyCyl(CamScrew[OD],CamScrew[LENGTH] + Protrusion,6);
	}

	for (j=[-1,1]) // Pi case screw inserts
	translate([0,j*PiSlotOC.y/2 + PiSlotOffset.y,-Protrusion] + PiPlateOffset)
	PolyCyl(Insert[OD],2*PiPlate.z,6);

	translate([-PiPlate.x/2 + (PiPlate.x – CamBox.x)/4,0,PlateThick – TextDepth/2] + PiPlateOffset)
	cube([15.0,30.0,TextDepth + Protrusion],center=true);
	}

	translate([-PiPlate.x/2 + (PiPlate.x – CamBox.x)/4 + 3,0,PlateThick – TextDepth – Protrusion] + PiPlateOffset)
	linear_extrude(height=TextDepth + Protrusion,convexity=2)
	rotate(-90)
	text("Ed Nisley",font="Arial:style=Bold",halign="center",valign="center",size=4,spacing=1.05);

	translate([-PiPlate.x/2 + (PiPlate.x – CamBox.x)/4 – 3,0,PlateThick – TextDepth – Protrusion] + PiPlateOffset)
	linear_extrude(height=TextDepth + Protrusion,convexity=2)
	rotate(-90)
	text("KE4ZNU",font="Arial:style=Bold",halign="center",valign="center",size=4,spacing=1.05);

view raw HQ Camera Backplate.scad hosted with ❤ by GitHub

2020-09-29

Bike Helmet Mirror: Brasswork Clamp

A bit of Quality Shop Time produced a slight improvement to the clamp holding the mirror to the stalk:

Helmet Mirror Ball Mount – mirror joint brasswork

The general idea is to hold the wave washer (it’s mashed under the flat washer, honest) above those bumps on the plate holding the mirror and stalk balls. It’s a few millimeters from the end of a ¼ inch brass rod, drilled for the M3 screw, and reduced to 4.5 mm with a parting tool to clear the bumps.

While I was at it, I made two spare mirrors, just to have ’em around:

Helmet Mirror Ball Mount – new vs old

The new ball mount looks downright svelte compared to the old Az-El mount, doesn’t it?

I should replace the steel clamp plates with a stainless-steel doodad of some sort to eliminate the unsightly rust, but that’s definitely in the nature of fine tuning.

2020-09-24
More AAA-to-AA Alkaline Adapters

Having a handful of not-dead-yet AAA alkalines and a bunch of LED blinkies built for AA alkalines, a pair of adapters seemed in order:

AAA-to-AA Alkaline Adapters – installed

The blinkies need a somewhat wider base than they’d get from a pair of AAA alkalines, so it’s not quite as dumb as it may seem.

In any event, the positive terminal comes from a brass rod:

AAA-to-AA Alkaline Adapters – brass terminal

Nobody will ever see the fancy Hilbert Curve infill around the brass:

AAA-to-AA Alkaline Adapters – end view

In this application, they’ll go from not-dead-yet to oh-it’s-dead faster than AA cells, so I can watch how the blinkies work with lower voltages.

2020-09-23

Bike Helmet Mirror: Ball Mount

Nine years ago, I didn’t know ~~how~~ enough to design a bike helmet mirror with a ball mount, but even an old dog can learn a new trick:

Helmet Mirror Ball Mount - on helmet — Helmet Mirror Ball Mount – on helmet

However, it’s worth noting my original, butt-ugly Az-El mounts lasted for all of those nine years, admittedly with adjustments along the way, which is far more than the commercial mounts making me unhappy enough to scratch my itch.

The mount adapts the split spherical clamp from the daytime running light:

Helmet Mirror Mount - Ball — Helmet Mirror Mount – Ball

Scaling it down for a 10 mm polypropylene ball around the base of the 30 mm inspection mirror’s shaft simplified everything:

Helmet Mirror Ball Mount - drilled ball test — Helmet Mirror Ball Mount – drilled ball test

I’m reasonably sure I couldn’t have bought 100 polypro balls for eight bucks a decade ago, but we’ll never know. Drilling the hole was a complete botch job, about which more later. The shaft came from a spare mirror mount I made up a while ago; a new shaft appears below.

The solid model, like Gaul, is in three parts divided:

Helmet Mirror Ball Mount - Slic3r — Helmet Mirror Ball Mount – Slic3r

The helmet plate (on the right) has a slight indent more-or-less matching the helmet curvature and gets a layer of good double-stick foam tape. The clamp base (on the left) has a pair of brass inserts epoxied into matching recesses below the M3 clearance holes:

Helmet Mirror Ball Mount - inserts — Helmet Mirror Ball Mount – inserts

A layer of epoxy then sticks the helmet plate in place, with the inserts providing positive alignment:

Helmet Mirror Ball Mount - plates — Helmet Mirror Ball Mount – plates

The clamp screws pull the inserts against the plastic in the clamp base, so they can’t pull out or through, and the plates give the epoxy enough bonding surface that (I’m pretty sure) they won’t ever come apart.

I turned down a 2 mm brass insert to fit inside the butt end of the mirror shaft and topped it off with a random screw harvested from a dead hard drive:

Helmet Mirror Ball Mount - assembled - rear view — Helmet Mirror Ball Mount – assembled – rear view

At the start, it wasn’t obvious the shaft would stay stuck in the ball, so I figured making it impossible to pull out would eliminate the need to find it by the side of the road. As things turned out, the clamp exerts enough force to ensure the shaft ain’t goin’ nowhere, so I’ll plug future shafts with epoxy.

The front side of the clamp looks downright sleek:

Helmet Mirror Ball Mount - assembled - front view — Helmet Mirror Ball Mount – assembled – front view

Well, how about “chunky”?

The weird gray-black highlights are optical effects from clear / natural PETG, rather than embedded grunge; it looks better in person. I should have used retina-burn orange or stylin’ black.

This mount is much smaller than the old one and should, in the event of a crash, not cause much injury. Based on how the running light clamp fractures, I expect the clamp will simply tear out of the base on impact. In the last decade, neither of us has crashed, so I don’t know what the old mount would do.

The clamp is 7 mm thick (front-to-back), set by the M3 washer diameter, with 1.5 mm of ball sticking out on each side. The model has a kerf one thread high (0.25 mm) between the pieces to add clamping force and, with the screws tightened down, moving the ball requires a disturbingly large effort. I added a touch of rosin and that ball straight-up won’t move, which probably means the shaft will bend upon droppage; I have several spare mirrors in stock.

On the other paw, the ball turns smoothly in the clamp and it’s easy to position the shaft as needed: much better than the old Az-El mount!

The inspection mirror hangs from a double ball joint which arrives with a crappy screw + nut. I epoxied the old mirror mount nut in place, but this time around I drilled the plates for a 3 mm stainless SHCS, used a wave washer for a bit of flexible force, and topped it off with a nyloc nut:

Helmet Mirror Ball Mount - mirror joint — Helmet Mirror Ball Mount – mirror joint

I’m unhappy with how it looks and don’t like how the washer hangs in free space between those bumps, so I may eventually turn little brass fittings to even things out. It’s either that or more epoxy.

So far, though, it’s working pretty well and both units meet customer requirements.

The OpenSCAD source code as a GitHub Gist:

	// Bike helmet mirror mount – ball joint
	// Ed Nisley KE4ZNU 2020-09

	/* [Layout options] */

	Layout = "Build"; // [Build, Show, Plate, Base, Clamp]

	//– Extrusion parameters

	// Extrusion parameters

	/* [Hidden] */

	ThreadThick = 0.25;
	ThreadWidth = 0.40;

	HoleWindage = 0.2;

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

	Protrusion = 0.1; // make holes end cleanly

	inch = 25.4;

	ID = 0;
	OD = 1;
	LENGTH = 2;

	//- Basic dimensions

	MountDia = 30.0; // footprint on helmet

	BallDia = 10.0;
	BallRad = BallDia / 2;

	WallThick = IntegerMultiple(2.0,ThreadWidth);
	FloorThick = IntegerMultiple(2.0,ThreadThick);

	CornerRound = 2.0;

	Insert = [3.0,4.0,4.0]; // threaded brass insert
	Screw = [3.0,5.5,25.0]; // clamp screw
	Washer = [3.7,7.0,0.7]; // washer

	ShowGap = 2.0;
	BuildGap = 5.0;

	//– Helmet Interface Plate

	ScrewOC = BallDia + 2*WallThick + Screw[ID];
	echo(str("Screw OC: ",ScrewOC));

	Clamp = [ceil(Washer[OD]), // barely holds washer under screw
	ScrewOC + Washer[OD], // minimal clearance for washer
	BallDia +2*FloorThick // screw fits through insert
	];

	Kerf = ThreadThick;

	echo(str("Clamp: ",Clamp));

	HelmetCX = 60.0; // empirical helmet side curve
	HelmetMX = 3.0;
	HelmetRX = (pow(HelmetMX,2) + pow(HelmetCX,2)/4)/(2*HelmetMX);

	HelmetPlateC = MountDia;
	HelmetPlateTheta = atan(HelmetPlateC/HelmetRX);
	HelmetPlateM = 2HelmetRXpow(sin(HelmetPlateTheta/4),2);

	echo(str("Plate indent: ",HelmetPlateM));

	HelmetPlateThick = max(FloorThick,0.6*Insert[LENGTH]) + HelmetPlateM;

	echo(str("Screw length: ",Clamp.z + Insert[LENGTH]));

	MountSides = 234;

	//———————-
	// 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);
	}


	//———————-
	// Clamp frame around ball

	module ClampFrame() {

	difference() {
	union() {
	hull()
	for (i=[-1,1], j=[-1,1]) {
	translate([i(Clamp.x/2 – CornerRound),j(Clamp.y/2 – CornerRound),Clamp.z/2 – CornerRound])
	sphere(r=CornerRound,$fn=24);
	translate([i(Clamp.x/2 – CornerRound),j(Clamp.y/2 – CornerRound),-Clamp.z/2])
	cylinder(r=CornerRound,$fn=24);
	}
	for (j=[-1,1])
	translate([0,j*ScrewOC/2,0])
	rotate(180/12)
	cylinder(d=Washer[OD],h=Clamp.z/2,$fn=12);

	}

	sphere(d=BallDia + HoleWindage,$fn=48);

	cube([2MountDia,2MountDia,Kerf],center=true);

	for (j=[-1,1])
	translate([0,j*ScrewOC/2,-Screw[LENGTH]])
	rotate(180/6)
	PolyCyl(Screw[ID],2*Screw[LENGTH],6);
	}
	}

	module ClampSelect(Section) {
	XlateZ = (Section == "Top") ? Clamp.z/2 :
	(Section == "Bottom") ? -Clamp.z/2 :
	0;
	intersection(convexity=5) {
	ClampFrame();
	translate([0,0,XlateZ])
	cube([2Clamp.x,2Clamp.y,Clamp.z + 2*Protrusion],center=true);

	}
	}

	//———————-
	// Concave plate fitting helmet shell

	module HelmetPlate() {

	render()
	difference() {
	cylinder(d=MountDia,h=HelmetPlateThick,$fn=MountSides);

	translate([0,0,HelmetPlateThick – HelmetPlateM + HelmetRX])
	sphere(r=HelmetRX,$fn=128);

	for (j=[-1,1])
	translate([0,j*ScrewOC/2,-Protrusion]) {
	PolyCyl(Insert[OD],0.6*Insert[LENGTH] + Protrusion,6);
	PolyCyl(Screw[ID],2*HelmetPlateThick,6);
	}
	}

	}

	//———————-
	// Base of clamp ring

	module MountBase() {

	difference() {
	union() {
	cylinder(d=MountDia,h=FloorThick,$fn=MountSides);
	translate([0,0,FloorThick + Clamp.z/2])
	ClampSelect("Bottom");
	}

	for (j=[-1,1])
	translate([0,j*ScrewOC/2,-Protrusion])
	rotate(180/6)
	PolyCyl(Insert[OD],0.6*Insert[LENGTH] + Protrusion,6);
	}
	}


	//———————-
	// Lash it together


	if (Layout == "Plate") {
	HelmetPlate();
	}

	if (Layout == "Base") {
	MountBase();
	}

	if (Layout == "Clamp") {
	ClampFrame();
	}



	if (Layout == "Show") {
	rotate([180,0,0])
	HelmetPlate();
	translate([0,0,ShowGap]) {
	MountBase();
	color("Ivory",0.3)
	translate([0,0,Clamp.z/2 + FloorThick + ShowGap/2])
	sphere(d=BallDia);
	translate([0,0,Clamp.z/2 + FloorThick + ShowGap])
	ClampSelect("Top");
	}
	}


	if (Layout == "Build") {
	translate([MountDia/2 + BuildGap,0,0])
	HelmetPlate();
	translate([-(MountDia/2 + BuildGap),0,0])
	MountBase();
	translate([0,MountDia/2 + BuildGap,Clamp.z/2])
	rotate([0,180,0])
	rotate(90)
	ClampSelect("Top");
	}

view raw Helmet Mirror Mount – Ball.scad hosted with ❤ by GitHub

The original doodles include a bit of dress-up fairing that didn’t make the cut:

Helmet Mirror Ball Mount - doodles — Helmet Mirror Ball Mount – doodles

2020-09-18

Discrete LM3909: Blue LED Radome

Dropping a simplified ping-pong ball radome for a Piranha RGB LED atop a discrete LM3909 on the AA alkaline cell holder:

Discrete LM3909 Radome - AA alkaline — Discrete LM3909 Radome – AA alkaline

The solid model has screw holes for the lid and the revised LED spider:

Astable Multivibrator - Alkaline AA Base - radome - solid model — Astable Multivibrator – Alkaline AA Base – radome – solid model

The RGB LED needs only two wires, as the LM3909 circuit can blink only one LED. I tried all three colors, but only blue and green justify the LM3909 hairball; red can get along with the astable circuit.

The LED wires connect across a 1 MΩ resistor serving as a mechanical strut between the 9.1 kΩ resistor on the left and the 10 Ω ballast resistor on the right.

Fresh alkaline cells at 3.0 V put 3.3 V across the blue LED with a 37 mA peak current. Older cells at 2.3 V produce 2.9 V at 15 mA. Dead cells at 1.9 V still fire the LED with 2.7 V at 4.2 mA, although the flash is barely visible in ordinary room light.

The lovely blue ball looks better in person!

The OpenSCAD source code as a GitHub Gist:

	// Astable Multivibrator
	// Holder for Alkaline cells
	// Ed Nisley KE4ZNU August 2020
	// 2020-09 add LED radome

	/* [Layout options] */

	Layout = "Build"; // [Build,Show,Lid,Spider]

	/* [Hidden] */

	CellName = "AA"; // [AA] — does not work with anything else
	NumCells = 2; // [2] — likewise

	Struts = -1; // [0:None, -1:Dual, 1:Quad] — Quad is dead

	// Extrusion parameters

	/* [Hidden] */

	ThreadThick = 0.25;
	ThreadWidth = 0.40;

	HoleWindage = 0.2;

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

	Protrusion = 0.1; // make holes end cleanly

	inch = 25.4;

	//- Basic dimensions

	WallThick = IntegerMultiple(3.0,ThreadWidth);
	CornerRadius = WallThick/2;

	FloorThick = IntegerMultiple(3.0,ThreadThick);

	TopThick = IntegerMultiple(2.0,ThreadThick);

	WireOD = 1.5; // battery & LED wiring
	WireOC = 4;

	Gap = 5.0;

	// Cylindrical cell sizes
	// https://en.wikipedia.org/wiki/List_of_battery_sizes#Cylindrical_batteries

	CELL_NAME = 0;
	CELL_OD = 1;
	CELL_OAL = 2;

	// FIXME search() needs special-casing to properly find AAA and AAAA
	// Which is why CellName is limited to AA

	CellData = [
	["AAAA",8.3,42.5],
	["AAA",10.5,44.5],
	["AA",14.5,50.5],
	["C",26.2,50],
	["D",34.2,61.5],
	["A23",10.3,28.5],
	["CR123A",17.0,34.5],
	["18650",18.8,65.2], // bare 18650 with button end
	["18650Prot",19.0,70.0], // protected 18650 = 19670 plus a bit
	];

	CellIndex = search([CellName],CellData,1,0)[0];
	echo(str("Cell index: ",CellIndex," = ",CellData[CellIndex][CELL_NAME]));

	//- Contact dimensions

	CONTACT_NAME = 0;
	CONTACT_WIDE = 1;
	CONTACT_HIGH = 2;
	CONTACT_THICK = 3; // plate thickness
	CONTACT_TIP = 4; // tip to rear face
	CONTACT_TAB = 5; // solder tab width

	ContactData = [
	["AA+",12.2,12.2,0.3,1.7,3.5], // pos bump
	["AA-",12.2,12.2,0.3,5.0,3.5], // half-compressed neg spring
	["AA+-",28.2,12.2,0.3,5.0,0], // pos-neg bridge

	["Li+",18.5,16.0,0.3,2.8,5.5],
	["Li-",18.5,16.0,0.3,6.0,5.5],
	];

	function ConDat(name,dim) = ContactData[search([name],ContactData,1,0)[0]][dim];

	ContactRecess = 2*ConDat(str(CellName,"+"),CONTACT_THICK);
	ContactOC = CellData[CellIndex][CELL_OD];

	WireBay = 6.0; // room for wiring to contacts

	//- Wire struts

	StrutDia = 1.6; // AWG 14 = 1.6 mm
	StrutSides = 3*4;

	ID = 0;
	OD = 1;
	LENGTH = 2;

	StrutBase = [StrutDia,StrutDia + 25ThreadWidth, // ID = wire, OD = buildable
	FloorThick + CellData[CellIndex][CELL_OD]]; // LENGTH = base is flush with cell top

	//- Holder dimensions

	BatterySize = [CellData[CellIndex][CELL_OAL] + // cell
	ConDat(str(CellName,"+"),CONTACT_TIP) + // pos contact
	ConDat(str(CellName,"-"),CONTACT_TIP) – // neg contact
	2*ContactRecess, // sink into wall
	NumCells*CellData[CellIndex][CELL_OD],
	CellData[CellIndex][CELL_OD]
	];

	echo(str("Battery space: ",BatterySize));

	CaseSize = [3*WallThick + // end walls + wiring partition
	BatterySize.x + // cell
	WireBay, // wiring bay
	2*WallThick + BatterySize.y,
	FloorThick + BatterySize.z
	];

	BatteryOffset = (CaseSize.x – (2*WallThick +
	CellData[CellIndex][CELL_OAL] +
	ConDat(str(CellName,"-"),CONTACT_TIP))
	) /2 ;

	ThumbRadius = 0.75 * CaseSize.z;


	StrutOC = [IntegerLessMultiple(CaseSize.x – 2CornerRadius -2StrutBase[OD],5.0),
	IntegerMultiple(CaseSize.y + StrutBase[OD],5.0)];

	StrutAngle = atan(StrutOC.y/StrutOC.x);

	echo(str("Strut OC: ",StrutOC));

	LidSize = [2*WallThick + WireBay + ConDat(str(CellName,"+"),CONTACT_THICK), CaseSize.y, FloorThick/2];

	LidScrew = [2.0,3.8,7.0]; // M2 pan head screw (LENGTH = threaded)
	LidScrewOC = CaseSize.y/2 – CornerRadius – LidScrew[OD]; // allow space around screw head

	//- Piranha LEDs

	PiranhaBody = [8.0,8.0,8.0]; // Z = heatsink fins + body + lens height

	PiranhaPin = 0.0; // trimmed pin length beyond heatsink
	PiranhaPinsOC = [5.0,5.0]; // pin XY distance

	PiranhaRecess = PiranhaBody.z + PiranhaPin/2; // minimum LED recess depth

	BallOD = 40.0; // radome sphere
	BallSides = 4*StrutSides; // nice smoothness

	BallPillar = [norm([PiranhaBody.x,PiranhaBody.y]), // ID
	norm([PiranhaBody.x,PiranhaBody.y]) + 3*WallThick, // OD
	StrutBase[OD] + PiranhaBody.z]; // height to base of chord
	echo(str("Pillar OD: ",BallPillar[OD]));

	BallChordM = BallOD/2 – sqrt(pow(BallOD/2,2) – (pow(BallPillar[OD],2))/4);
	echo(str("Ball chord depth: ",BallChordM));


	//———————-
	// 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);
	}

	// Spider for single LED atop struts, with the ball

	module DualSpider() {

	difference() {
	union() {
	for (j=[-1,1]) {
	translate([0,j*StrutOC.y/2,StrutBase[OD]/2])
	rotate(180/StrutSides)
	sphere(d=StrutBase[OD]/cos(180/StrutSides),$fn=StrutSides);
	translate([0,j*StrutOC.y/2,0])
	rotate(180/StrutSides)
	cylinder(d=StrutBase[OD],h=StrutBase[OD]/2,$fn=StrutSides);
	}

	translate([0,0,StrutBase[OD]/4]) // connecting bars
	cube([StrutBase[OD]*cos(180/StrutSides),StrutOC.y,StrutBase[OD]/2],center=true);

	cylinder(d=BallPillar[OD],h=BallPillar[LENGTH],$fn=BallSides);
	}

	for (j=[-1,1]) // strut wires
	translate([0,j*StrutOC.y/2,-Protrusion])
	PolyCyl(StrutBase[ID],StrutBase[OD]/2,6);

	for (n=[-1,1]) // LED wiring
	rotate(n*90)
	translate([StrutOC.x/3,0,-Protrusion])
	PolyCyl(StrutBase[ID],StrutBase[OD],6);

	translate([0,0,BallOD/2 + BallPillar[LENGTH] – BallChordM]) // ball inset
	sphere(d=BallOD);

	translate([0,0,BallPillar.z – PiranhaRecess + BallPillar.z/2]) // LED inset
	cube(PiranhaBody + [HoleWindage,HoleWindage,BallPillar.z],center=true); // XY clearance

	translate([0,0,StrutBase[OD]/2 + WireOD/2 + 0*Protrusion]) // wire channels
	cube([WireOD,BallPillar[OD] + 2*WallThick,WireOD],center=true);

	}
	}

	//– Overall case with origin at battery center

	module Case() {

	union() {

	difference() {
	union() {
	hull()
	for (i=[-1,1], j=[-1,1])
	translate([i*(CaseSize.x/2 – CornerRadius),
	j*(CaseSize.y/2 – CornerRadius),
	0])
	cylinder(r=CornerRadius/cos(180/8),h=CaseSize.z,$fn=8); // cos() fixes undersize spheres!

	if (Struts)
	for (i = (Struts == 1) ? [-1,1] : -1) { // strut bases
	hull()
	for (j=[-1,1])
	translate([iStrutOC.x/2,jStrutOC.y/2,0])
	rotate(180/StrutSides)
	cylinder(d=StrutBase[OD],h=StrutBase[LENGTH],$fn=StrutSides);

	translate([i*StrutOC.x/2,0,StrutBase[LENGTH]/2])
	cube([2*StrutBase[OD],StrutOC.y,StrutBase[LENGTH]],center=true); // blocks for fairing

	for (j=[-1,1]) // hemisphere caps
	translate([i*StrutOC.x/2,
	j*StrutOC.y/2,
	StrutBase[LENGTH]])
	rotate(180/StrutSides)
	sphere(d=StrutBase[OD]/cos(180/StrutSides),$fn=StrutSides);

	}
	}

	translate([BatteryOffset,0,BatterySize.z/2 + FloorThick]) // cells
	cube(BatterySize + [0,0,Protrusion],center=true);

	translate([BatterySize.x/2 + BatteryOffset + ContactRecess/2 – Protrusion/2, // contacts
	0,
	BatterySize.z/2 + FloorThick])
	cube([ContactRecess + Protrusion,
	ConDat(str(CellName,"+-"),CONTACT_WIDE),
	ConDat(str(CellName,"+-"),CONTACT_HIGH)
	],center=true);

	translate([-(BatterySize.x/2 – BatteryOffset + ContactRecess/2 – Protrusion/2),
	ContactOC/2,
	BatterySize.z/2 + FloorThick])
	cube([ContactRecess + Protrusion,
	ConDat(str(CellName,"+"),CONTACT_WIDE),
	ConDat(str(CellName,"+"),CONTACT_HIGH)
	],center=true);

	translate([-(BatterySize.x/2 – BatteryOffset + ContactRecess/2 – Protrusion/2),
	-ContactOC/2,
	BatterySize.z/2 + FloorThick])
	cube([ContactRecess + Protrusion,
	ConDat(str(CellName,"-"),CONTACT_WIDE),
	ConDat(str(CellName,"-"),CONTACT_HIGH)
	],center=true);

	translate([-CaseSize.x/2 + WireBay/2 + WallThick, // wire bay with screw bosses
	0,
	BatterySize.z/2 + FloorThick + Protrusion/2])
	cube([WireBay,
	2LidScrewOC – LidScrew[ID] – 24*ThreadWidth,
	BatterySize.z + Protrusion
	],center=true);

	for (j=[-1,1]) // screw holes
	translate([-CaseSize.x/2 + WireBay/2 + WallThick,
	j*LidScrewOC,
	CaseSize.z – LidScrew[LENGTH] + Protrusion])
	PolyCyl(LidScrew[ID],LidScrew[LENGTH],6);


	for (j=[-1,1])
	translate([-(BatterySize.x/2 – BatteryOffset + WallThick/2), // contact tabs
	j*ContactOC/2,
	BatterySize.z + FloorThick – Protrusion])
	cube([2*WallThick,
	ConDat(str(CellName,"+"),CONTACT_TAB),
	(BatterySize.z – ConDat(str(CellName,"+"),CONTACT_HIGH))
	],center=true);

	if (false)
	translate([0,0,CaseSize.z]) // finger cutout
	rotate([90,00,0])
	cylinder(r=ThumbRadius,h=2*CaseSize.y,center=true,$fn=22);

	translate([0,0,ThreadThick – Protrusion]) // recess around name
	cube([0.6CaseSize.x,8,2ThreadThick],center=true);

	if (Struts)
	for (i2 = (Struts == 1) ? [-1,1] : -1) { // strut wire holes and fairing
	for (j=[-1,1])
	translate([i2StrutOC.x/2,jStrutOC.y/2,FloorThick])
	rotate(180/StrutSides)
	PolyCyl(StrutBase[ID],2*StrutBase[LENGTH],StrutSides);

	for (i=[-1,1], j=[-1,1]) // fairing cutaways
	translate([iStrutBase[OD] + (i2StrutOC.x/2),
	j*StrutOC.y/2,
	-Protrusion])
	rotate(180/StrutSides)
	PolyCyl(StrutBase[OD],StrutBase[LENGTH] + 2*Protrusion,StrutSides);
	}

	}

	translate([0,0,0])
	linear_extrude(height=2*ThreadThick + Protrusion,convexity=10)
	mirror([0,1,0])
	text(text="KE4ZNU",size=6,spacing=1.20,font="Arial:style:Bold",halign="center",valign="center");

	}
	}


	module Lid() {

	difference() {
	hull()
	for (i=[-1,1], j=[-1,1], k=[-1,1])
	translate([i*(LidSize.x/2 – CornerRadius),
	j*(LidSize.y/2 – CornerRadius),
	k*(LidSize.z – CornerRadius)]) // double thickness for flat bottom
	sphere(r=CornerRadius/cos(180/8),$fn=8);

	translate([0,0,-LidSize.z]) // remove bottom
	cube([(LidSize.x + 2Protrusion),(LidSize.y + 2Protrusion),2*LidSize.z],center=true);

	for (j=[-1,1]) // wire holes
	translate([0,j*WireOC,-Protrusion])
	PolyCyl(WireOD,2*LidSize.z,6);

	for (j=[-1,1])
	translate([0,j*LidScrewOC,-Protrusion])
	PolyCyl(LidScrew[ID],2*LidSize.z,6);

	}
	}


	//——————-
	// Build it!

	if (Layout == "Case")
	Case();

	if (Layout == "Lid")
	Lid();

	if (Layout == "Spider")
	if (Struts == -1)
	DualSpider();
	else
	cube(10,center=true);

	if (Layout == "Build") {
	rotate(90)
	Case();
	translate([0,-(CaseSize.x/2 + LidSize.x/2 + Gap),0])
	rotate(90)
	Lid();
	if (Struts == -1)
	translate([CaseSize.x/2,0,0])
	DualSpider();
	}

	if (Layout == "Show") {
	Case();
	translate([-CaseSize.x/2 + LidSize.x/2,0,(CaseSize.z + Gap)])
	Lid();
	}

view raw Astable Multivibrator – Alkaline Batteries – radome.scad hosted with ❤ by GitHub

2020-09-17

Tag: M2

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