Tag: Improvements

Making the world a better place, one piece at a time

Astable Multivibrator: SMT LED Ballast Resistor

The original astable multivibrator ran from a dead CR123 primary lithium cell:

CR123A Astable – front

With a terminal voltage falling from barely 3 V, the LED drew about 3 mA (1 mA/div), tops, without a ballast resistor:

Astable – CR123A 2.8 V – 1 mA -green

Hacking in a charged NP-BX1 secondary lithium cell boosted the supply to 4 V:

NP-BX1 Holder – SMT pogo pins

Which, diodes being the way they are, raised the LED current to nearly 400 mA (100 mA/div):

Astable – NP-BX1 4V – base V – 100mA-div

Somewhat to my surprise, a few weeks of abuse didn’t do any obvious damage to the LED, but I added a resistor while I was soldering up another holder:

Astable – 51 ohm SMD ballast

There’s not quite enough room for a 1/8 W axial resistor, so why not blob in a surface-mount resistor?

Which cuts the current down to a mere 15 mA (10 mA/div) from a lithium battery at 4 V:

Astable – NP-BX1 – 51 ohm ballast – 10ma-div

It’s still blindingly bright, but now I don’t feel bad about it.

2018-12-14
Desk Drawer Stops

The stops aligning the top two drawers of an old desk vanished, so I got the job of replacing them. They’re hammered into the wood frame:

Drawer Stops – width measurement

And stand up just enough to engage the back of the drawer face:

Drawer Stops – height measurement

Back in the Basement Laboratory Shop Wing, I harvested steel strips from a defunct PC case, rubber-hammered them flat, sharpened a cold chisel (un-hardened, so it always needs sharpening), and got to work:

Drawer Stops – chiseled blanks

The pointy sides should have sharp edges, which you get for free with a chisel. You also get a bench full of little steel slivers perfectly suited for embedding in human flesh. Wearing eye protection is more than just a good idea, too.

Introducing what will become the visible edges to Mr Disk Sander makes them marginally less hazardous:

Drawer Stops – in progress

A slightly fuzzy picture of a test fit shows the stops should suffice:

Drawer Stops – trial fit

Which they did:

Drawer Stops – installed

Nobody will ever notice the blob of hot melt glue behind each one:

Drawer Stops – glue blob

Done!

2018-12-13

Astable Multivibrator: NP-BX1 Base

Adapting the NP-BX1 battery holder to use SMT pogo pins worked well:

NP-BX1 Holder - SMT pogo pins — NP-BX1 Holder – SMT pogo pins

The next step is to add sockets for those 14 AWG wires:

NP-BX1 Battery Holder - Wire Posts - solid model — NP-BX1 Battery Holder – Wire Posts – solid model

Start by reaming / hand-drilling all the holes to their nominal size and cleaning out the pogo pin pocket.

Solder wires to the pogo pins and thread them through the holder and lid:

Astable - NP-BX1 holder - pogo pin soldering — Astable – NP-BX1 holder – pogo pin soldering

That’s nice, floppy silicone-insulated 24 AWG wire, which may be a bit too thick for this purpose.

The pogo pins will, ideally, seat with the end of the body flush at the holder wall. Make it so:

Astable - NP-BX1 holder - pogo pin protrusion — Astable – NP-BX1 holder – pogo pin protrusion

Dress the wires neatly into their pocket:

Astable - NP-BX1 holder - pogo pin wiring — Astable – NP-BX1 holder – pogo pin wiring

Butter the bottom of the lid with epoxy, clamp in place, set it up for curing, then fill the recess:

Astable - NP-BX1 base - curing — Astable – NP-BX1 base – curing

While it’s curing, make a soldering fixture for the 14 AWG wires:

Astable - drilling strut soldering fixture — Astable – drilling strut soldering fixture

The holes are on 5 mm centers, in the expectation other battery holders will need different spacing.

Solder it up and stick the wires into the base:

Astable - NP-BX1 base - detail — Astable – NP-BX1 base – detail

Jam a battery in and It Just Works™:

Astable - NP-BX1 3.8V - 20ma-div - cap V — Astable – NP-BX1 3.8V – 20ma-div – cap V

The traces:

Green = supply current at 20 mA/div
Yellow = LED driver transistor base voltage
Purple = other transistor collector voltage
White = base – collector voltage = capacitor voltage

The measurement setup was a bit of a hairball:

Astable - NP-BX1 base - current probe — Astable – NP-BX1 base – current probe

For completeness, here’s the schematic-and-layout diagram behind the circuitry:

Astable - NP-BX1 base - schematic — Astable – NP-BX1 base – schematic

I love it when a plan comes together!

The OpenSCAD source code as a GitHub Gist:

	// Holder for Sony NP-BX1 Li-Ion battery
	// Ed Nisley KE4ZNU January 2013
	// 2018-11-15 Adapted for wire leads from 1.5 mm test pins, added upright wire bases

	// Layout options

	Layout = "Fit"; // Show Build Fit Case Lid Pins

	//- Extrusion parameters – must match reality!
	// Print with +2 shells and 3 solid layers

	ThreadThick = 0.25;
	ThreadWidth = 0.35;

	HoleWindage = 0.2;

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

	Protrusion = 0.1; // make holes end cleanly

	inch = 25.4;

	BuildOffset = 3.0; // clearance for build layout

	Gap = 2.0; // separation for Fit parts

	//- Basic dimensions

	WallThick = 4*ThreadWidth; // holder sidewalls

	BaseThick = 6*ThreadThick; // bottom of holder to bottom of battery
	TopThick = 6*ThreadThick; // top of battery to top of holder


	//- Battery dimensions – rationalized from several samples
	// Coordinate origin at battery contact face with key openings below contacts

	Battery = [43.0,30.0,9.5]; // X = length, Y = width, Z = thickness

	Contacts = [[-0.75,6.0,6.2],[-0.75,16.0,6.2]]; // relative to battery edge, front, and bottom
	ContactOC = Contacts[1].y – Contacts[0].y;
	ContactCenter = Contacts[0].y + ContactOC/2;

	KeyBlocks = [[1.75,3.70,2.90],[1.75,3.60,2.90]]; // recesses in battery face set X position

	//- Pin dimensions

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

	PinShank = [1.5,2.0,6.5]; // shank, flange, compressed length
	PinFlange = [1.5,2.0,0.5]; // flange, length included in PinShank
	PinTip = [0.9,0.9,2.5]; // extended spring-loaded tip

	PinChannel = PinFlange[LENGTH] + 0.5; // cut behind flange for solder overflow
	PinRecess = 3.0; // recess behind pin flange end for epoxy fill

	echo(str("Contact tip dia: ",PinTip[OD]));
	echo(str(" .. shank dia: ",PinShank[ID]));

	OverTravel = 0.5; // space beyond battery face at X origin

	//- Holder dimensions

	GuideRadius = ThreadWidth; // friction fit ridges
	GuideOffset = 7; // from compartment corners

	ThumbRadius = 10.0; // thumb opening at end of battery

	CornerRadius = 3*ThreadThick; // nice corner rounding

	CaseSize = [Battery.x + PinShank[LENGTH] + OverTravel + PinRecess + GuideRadius + WallThick,
	Battery.y + 2WallThick + 2GuideRadius,
	Battery.z + BaseThick + TopThick];

	CaseOffset = [-(PinShank[LENGTH] + OverTravel + PinRecess),-(WallThick + GuideRadius),0]; // position around battery

	LidOverhang = 2.0; // over top of battery for retention

	LidSize = [-CaseOffset.x + LidOverhang,CaseSize.y,TopThick];

	LidOffset = [0.0,CaseOffset.y,0];

	//- Wire struts

	StrutDia = 1.6; // AWG 14 = 1.6 mm
	StrutOC = 45;
	StrutSides = 3*4;

	StrutBase = [StrutDia,StrutDia + 4*WallThick,CaseSize.z – TopThick]; // ID = wire, OD=buildable

	//———————-
	// 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);
	}

	//——————-
	//– Guides for tighter friction fit

	module Guides() {
	translate([GuideOffset,-GuideRadius,0])
	PolyCyl(2*GuideRadius,(Battery.z – Protrusion),4);
	translate([GuideOffset,(Battery.y + GuideRadius),0])
	PolyCyl(2*GuideRadius,(Battery.z – Protrusion),4);
	translate([(Battery.x – GuideOffset),-GuideRadius,0])
	PolyCyl(2*GuideRadius,(Battery.z – Protrusion),4);
	translate([(Battery.x – GuideOffset),(Battery.y + GuideRadius),0])
	PolyCyl(2*GuideRadius,(Battery.z – Protrusion),4);
	translate([(Battery.x + GuideRadius),GuideOffset/2,0])
	PolyCyl(2*GuideRadius,(Battery.z – Protrusion),4);
	translate([(Battery.x + GuideRadius),(Battery.y – GuideOffset/2),0])
	PolyCyl(2*GuideRadius,(Battery.z – Protrusion),4);

	}

	//– Contact pins
	// Rotated to put them in their natural oriention
	// Aligned to put tip base / end of shank at Overtravel limit

	module PinShape() {

	translate([-(PinShank[LENGTH] + OverTravel),0,0])
	rotate([0,90,0])
	rotate(180/6)
	union() {
	PolyCyl(PinTip[OD],PinShank[LENGTH] + PinTip[LENGTH],6);
	PolyCyl(PinShank[ID],PinShank[LENGTH] + Protrusion,6); // slight extension for clean cuts
	PolyCyl(PinFlange[OD],PinFlange[LENGTH],6);
	}
	}

	// Position pins to put end of shank at battery face
	// Does not include recess access into case

	module PinAssembly() {

	union() {
	for (p = Contacts)
	translate([0,p.y,p.z])
	PinShape();

	translate([-(PinShank[LENGTH] + OverTravel) + PinChannel/2, // solder space
	ContactCenter,
	Contacts[0].z])
	cube([PinChannel,(Contacts[1].y – Contacts[0].y),PinFlange[OD]],center=true);

	for (j=[-1,1]) // wire channels
	translate([-(PinShank[LENGTH] + OverTravel – PinChannel/2),
	j*ContactOC/4 + ContactCenter,
	Contacts[0].z – PinFlange[OD]/2])
	rotate(180/6)
	PolyCyl(PinFlange[OD],CaseSize.z,6);
	}
	}

	//– Case with origin at battery corner

	module Case() {

	difference() {

	union() {

	difference() {
	union() {
	translate([(CaseSize.x/2 + CaseOffset.x), // basic case shape
	(CaseSize.y/2 + CaseOffset.y),
	(CaseSize.z/2 – BaseThick)])
	hull()
	for (i=[-1,1], j=[-1,1], k=[-1,1])
	translate([i*(CaseSize.x/2 – CornerRadius),
	j*(CaseSize.y/2 – CornerRadius),
	k*(CaseSize.z/2 – CornerRadius)])
	sphere(r=CornerRadius/cos(180/8),$fn=8); // cos() fixes undersize spheres!

	hull() // wire strut bases
	for (j=[-1,1])
	translate([0,j*StrutOC/2 + Battery.y/2,-BaseThick])
	rotate(180/StrutSides)
	cylinder(d=StrutBase[OD],h=StrutBase[LENGTH],$fn=StrutSides);

	translate([0,Battery.y/2,StrutBase[LENGTH]/2 – BaseThick])
	cube([2*StrutBase[OD],StrutOC,StrutBase[LENGTH]],center=true);
	}

	translate([-OverTravel,-GuideRadius,0])
	cube([(Battery.x + GuideRadius + OverTravel),
	(Battery.y + 2*GuideRadius),
	(Battery.z + Protrusion)]); // battery space
	}

	Guides(); // improve friction fit

	translate([-OverTravel,-GuideRadius,0]) // battery keying blocks
	cube(KeyBlocks[0] + [OverTravel,GuideRadius,0],center=false);
	translate([-OverTravel,(Battery.y – KeyBlocks[1].y),0])
	cube(KeyBlocks[1] + [OverTravel,GuideRadius,0],center=false);

	}

	translate([2*CaseOffset.x, // battery top access
	(CaseOffset.y – Protrusion),
	Battery.z])
	cube([2CaseSize.x,(CaseSize.y + 2Protrusion),(TopThick + Protrusion)]);

	if (false)
	translate([(CaseOffset.x – Protrusion), // battery insertion allowance
	(CaseOffset.y – Protrusion),
	Battery.z])
	cube([(CaseSize.x + 2Protrusion),(CaseSize.y + 2Protrusion),(TopThick + Protrusion)]);

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

	for (i=[-1,1], j=[-1,1])
	translate([iStrutBase[OD],jStrutOC/2 + Battery.y/2,-(BaseThick + Protrusion)])
	rotate(180/StrutSides)
	PolyCyl(StrutBase[OD],StrutBase[LENGTH] + 2*Protrusion,StrutSides);

	translate([(Battery.x – Protrusion), // remove thumb notch
	(CaseSize.y/2 + CaseOffset.y),
	(ThumbRadius)])
	rotate([90,0,0])
	rotate([0,90,0])
	cylinder(r=ThumbRadius,
	h=(WallThick + GuideRadius + 2*Protrusion),
	$fn=22);

	PinAssembly();

	translate([CaseOffset.x + PinRecess + Protrusion,(Contacts[1].y + Contacts[0].y)/2,Contacts[0].z])
	translate([-PinRecess,0,0])
	cube([2*PinRecess,
	(Contacts[1].y – Contacts[0].y + PinFlange[OD]),
	2*PinFlange[OD]],center=true);

	}

	}

	// Lid position offset to match case

	module Lid() {

	difference() {
	translate([-LidSize.x/2 + LidOffset.x + LidOverhang,LidSize.y/2 + LidOffset.y,0])
	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,$fn=8);

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

	translate([LidSize.x/8,0,0])
	cube([LidSize.x/4,0.75LidSize.y,4ThreadThick],center=true); // epoxy recess
	}

	translate([0,0,-(Contacts[0].z + PinFlange[OD])]) // punch wire holes
	PinAssembly();
	}

	}


	//——————-
	// Build it!

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

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

	if (Layout == "Pins") {
	color("Silver",0.5)
	PinShape();
	PinAssembly();
	}

	if (Layout == "Show") { // reveal pin assembly
	difference() {
	Case();

	translate([(CaseOffset.x – Protrusion),
	Contacts[1].y,
	Contacts[1].z])
	cube([(-CaseOffset.x + Protrusion),
	CaseSize.y,
	(CaseSize.z – Contacts[0].z + Protrusion)]);

	translate([(CaseOffset.x – Protrusion),
	(CaseOffset.y – Protrusion),
	0])
	cube([(-CaseOffset.x + Protrusion),
	Contacts[0].y + Protrusion – CaseOffset.y,
	CaseSize.z]);
	}

	translate([0,0,Battery.z + Gap])
	Lid();

	color("Silver",0.15)
	PinAssembly();

	}

	if (Layout == "Build") {
	translate([-(CaseSize.x/2 + CaseOffset.x),-(CaseOffset.y – BuildOffset),BaseThick])
	Case();
	translate([CaseSize.x/2,-LidSize.x/2,0])
	rotate(90)
	Lid();
	}

	if (Layout == "Fit") {
	Case();
	translate([0,0,(Battery.z + Gap)])
	Lid();
	color("Silver",0.25)
	PinAssembly();
	}

view raw NP-BX1 Battery Holder – Wire Posts.scad hosted with ❤ by GitHub

2018-12-12

Halogen Desk Lamp Conversion

As part of converting the halogen desk lamp to LEDs, I replaced the hulking iron transformer with a flatter counterweight:

Halogen Desk Lamp – 12 V 20 W transformer

Under normal circumstances, you’d use something like steel or lead sheets, but Tiny Bandsaw™ can’t cut any appreciable thickness of steel and I gave away my entire lead stockpile, so I sawed disks from a pile of non-stick pancake griddles and drilled suitable mounting holes:

Parallel clamps in action

Another disk (from a formal aluminum sheet!) goes into the lamp head, with a trio of 3W COB LEDs epoxied in place:

Ex-Halogen Desk Lamp – 3x3W COB LED assembly

The other side of the disk sports a heatsink harvested from a PC, also epoxied in place:

Ex-halogen Desk Lamp – heatsink fitting

Realizing the head required only a little filing to accommodate the heatsink sealed both their fates.

A test firing showed the heatsink needed more airflow, which didn’t come as much of a surprise, so I milled slots in the lamp head:

Ex-halogen Desk Lamp – vent slot milling

Deburring the holes, blackening the sides with a Sharpie, and tucking a bit of black window screen behind the opening made the vents look entirely professional.

The small dome in the base originally cleared the transformer and now holds the entire 10 W LED driver, along with all the wiring, atop the counterweight sheets:

Ex-halogen Desk Lamp – base wiring

A cork pad covers the base for a bit of non-skid action:

Ex-halogen Desk Lamp – cork pad

I couldn’t convince myself filling in those sectors would improve anything, so I didn’t.

And then It Just Worked:

Ex-halogen Desk Lamp – in use

All without a trace of solid modeling or G-Code …

2018-12-07
JYE Tech DSO150 Oscilloscope: Battery Power
With the DSO150 scope running, I printed Geoff’s DSO150 case + battery holder from Thingiverse, added a few bits & pieces from the heap, and came up with a completely portable scope:

DSO150 battery hack – first light

The only scope mod consists of embedding a JST-ish connector in the back panel:

DSO150 battery hack – rear panel connector

Then soldering it to the battery pads and applying generous hot-melt glue blobs:

DSO150 battery hack – PCB power

Add a scrap 18650 Li-Ion cell, a regulated boost converter, and a switch:

DSO150 battery hack – interior

The switch is directly below the DSO150 BNC connector to get a little protection for its handle, which would otherwise stick out in harm’s way. This being an afterthought, I drilled the switch hole, rather than modify the solid model.

Some testing with a bench supply showed that the DSO150 will not operate correctly from the voltages produced by a pair of lithium cells, despite what you’d think from looking at the case. Below 8 V, the internally generated negative supply becomes larger than the positive supply, so the 0 V point isn’t properly centered and the scope loses headroom for large signals; monitoring the internal 3.3 V test signal makes the problem painfully obvious.

More color commentary from my summary email:
- Combining a case from Thingiverse with a Li-Ion cell and a regulated boost converter produces a portable scope.
- The PCB has provision for battery input, so I drilled / filed a square hole for a teeny JST-ish connector on the back panel, secured it with a blob of hot melt glue, and globbed the wires onto the PCB battery pads.
- The boost converter draws about 400 mA from the cell, so a 2500-ish mA·h cell should last Long Enough™. This is a scrap cell from the recycle box and gave out after maybe four hours.
- It idles at 8 mA, so I drilled a hole in the back of the case for a toggle switch disconnecting the battery; you’d want the hole in the solid model. Perhaps a better converter would have lower idle current; you’d never be able to tell from the eBay descriptions.
- Aaaaand it switches around 200 kHz under load, just barely beyond the scope bandwidth. It doesn’t add much noise to the signal, at least with a 50 Ω terminator jammed in the BNC, but the square-wave “cal” output looks awful at 50 mV/div; a real scope shows even more noise. I assume the noise comes directly from the logic supply; with luck, the DSO150’s analog circuitry has Good Enough™ filtering.
- Which might not matter for logic-level and moderate analog signals, of course, which is the whole point of the DSO150.
- Conspicuous by their absence: a Li-Ion cell protection PCB and any way to recharge the poor thing …
I’ve occasionally wanted a portable scope and now I have one!
2018-12-05

Sony NP-BX1 Battery Holder: SMT Pogo Pin Contacts

The original camera battery test fixtures used contact pins conjured from hulking gold-plated connector pins and coil springs:

Canon NB-6L holder - contact pin detail — Canon NB-6L holder – contact pin detail

The Sony HDR-AS30V camera chewed up and spat out a handful of batteries, all tested in the NP-BX1 test fixture:

NP-BX1 Holder - show layout — NP-BX1 Holder – show layout

Nowadays, SMT pogo pins produce a much more compact holder, so I figured I could put all those batteries to good use:

That’s the long-suffering astable multivibrator, still soldered to its CR123A holder.

Obviously, the battery holder should grow ears to anchor the 14 AWG copper posts and would look better in black PETG:

NP-BX1 Battery Holder - 1.5mm pins - solid model — NP-BX1 Battery Holder – 1.5mm pins – solid model

The battery lead wires get soldered to the ends of the pogo pins and are recessed into the slot in the end of the fixture. I used clear epoxy to anchor everything in place.

Fits perfectly and works fine!

The OpenSCAD source code as a GitHub Gist:

	// Holder for Sony NP-BX1 Li-Ion battery
	// Ed Nisley KE4ZNU January 2013
	// 2018-11-15 Adapted for wire leads from 1.5 mm test pins, added upright wire bases

	// Layout options

	Layout = "Show"; // Show Build Fit Case Lid Pins

	//- Extrusion parameters – must match reality!
	// Print with +2 shells and 3 solid layers

	ThreadThick = 0.25;
	ThreadWidth = 0.35;

	HoleWindage = 0.2;

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

	Protrusion = 0.1; // make holes end cleanly

	inch = 25.4;

	BuildOffset = 3.0; // clearance for build layout

	Gap = 2.0; // separation for Fit parts

	//- Battery dimensions – rationalized from several samples
	// Coordinate origin at battery contact face with key openings below contacts

	Battery = [43.0,30.0,9.5]; // X = length, Y = width, Z = thickness

	Contacts = [[-0.75,6.0,6.2],[-0.75,16.0,6.2]]; // relative to battery edge, front, and bottom

	KeyBlocks = [[1.75,3.70,2.90],[1.75,3.60,2.90]]; // recesses in battery face set X position

	//- Pin dimensions

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

	PinShank = [1.5,2.0,6.5]; // shank, flange, compressed length
	PinFlange = [1.5,2.0,0.5]; // flange, length included in PinShank
	PinTip = [0.9,0.9,2.5]; // extended spring-loaded tip

	PinChannel = PinFlange[LENGTH] + 0.5; // cut behind flange for solder overflow
	PinRecess = 3.0; // recess behind pin flange end for epoxy fill


	echo(str("Contact tip dia: ",PinTip[OD]));
	echo(str(" .. shank dia: ",PinShank[ID]));

	OverTravel = 0.5; // space beyond battery face at X origin

	//- Holder dimensions

	GuideRadius = ThreadWidth; // friction fit ridges
	GuideOffset = 7; // from compartment corners
	WallThick = 4*ThreadWidth; // holder sidewalls

	BaseThick = 6*ThreadThick; // bottom of holder to bottom of battery
	TopThick = 6*ThreadThick; // top of battery to top of holder

	ThumbRadius = 10.0; // thumb opening at end of battery

	CornerRadius = 3*ThreadThick; // nice corner rounding

	CaseSize = [Battery.x + PinShank[LENGTH] + OverTravel + PinRecess + GuideRadius + WallThick,
	Battery.y + 2WallThick + 2GuideRadius,
	Battery.z + BaseThick + TopThick];

	CaseOffset = [-(PinShank[LENGTH] + OverTravel + PinRecess),-(WallThick + GuideRadius),0]; // position around battery

	LidOverhang = 2.0; // over top of battery for retention

	LidSize = [-CaseOffset.x + LidOverhang,CaseSize.y,TopThick];

	LidOffset = [0.0,CaseOffset.y,0];

	//———————-
	// 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);
	}

	//——————-
	//– Guides for tighter friction fit

	module Guides() {
	translate([GuideOffset,-GuideRadius,0])
	PolyCyl(2*GuideRadius,(Battery.z – Protrusion),4);
	translate([GuideOffset,(Battery.y + GuideRadius),0])
	PolyCyl(2*GuideRadius,(Battery.z – Protrusion),4);
	translate([(Battery.x – GuideOffset),-GuideRadius,0])
	PolyCyl(2*GuideRadius,(Battery.z – Protrusion),4);
	translate([(Battery.x – GuideOffset),(Battery.y + GuideRadius),0])
	PolyCyl(2*GuideRadius,(Battery.z – Protrusion),4);
	translate([(Battery.x + GuideRadius),GuideOffset/2,0])
	PolyCyl(2*GuideRadius,(Battery.z – Protrusion),4);
	translate([(Battery.x + GuideRadius),(Battery.y – GuideOffset/2),0])
	PolyCyl(2*GuideRadius,(Battery.z – Protrusion),4);

	}

	//– Contact pins
	// Rotated to put them in their natural oriention
	// Aligned to put tip base / end of shank at Overtravel limit

	module PinShape() {

	translate([-(PinShank[LENGTH] + OverTravel),0,0])
	rotate([0,90,0])
	rotate(180/6)
	union() {
	PolyCyl(PinTip[OD],PinShank[LENGTH] + PinTip[LENGTH],6);
	PolyCyl(PinShank[ID],PinShank[LENGTH] + Protrusion,6); // slight extension for clean cuts
	PolyCyl(PinFlange[OD],PinFlange[LENGTH],6);
	}
	}

	// Position pins to put end of shank at battery face
	// Add wire exit channel between pins
	// Does not include recess access

	module PinAssembly() {

	union() {
	for (p = Contacts)
	translate([0,p.y,p.z])
	PinShape();
	translate([-(PinShank[LENGTH] + OverTravel) + PinChannel/2,
	(Contacts[1].y + Contacts[0].y)/2,
	Contacts[0].z])
	cube([PinChannel,(Contacts[1].y – Contacts[0].y),PinFlange[OD]],center=true);
	}
	}

	//– Case with origin at battery corner

	module Case() {

	difference() {

	union() {

	difference() {

	translate([(CaseSize.x/2 + CaseOffset.x), // basic case shape
	(CaseSize.y/2 + CaseOffset.y),
	(CaseSize.z/2 – BaseThick)])
	hull()
	for (i=[-1,1], j=[-1,1], k=[-1,1])
	translate([i*(CaseSize.x/2 – CornerRadius),
	j*(CaseSize.y/2 – CornerRadius),
	k*(CaseSize.z/2 – CornerRadius)])
	sphere(r=CornerRadius,$fn=8);

	translate([-OverTravel,-GuideRadius,0])
	cube([(Battery.x + GuideRadius + OverTravel),
	(Battery.y + 2*GuideRadius),
	(Battery.z + Protrusion)]); // battery space
	}

	Guides(); // improve friction fit

	translate([-OverTravel,-GuideRadius,0]) // battery keying blocks
	cube(KeyBlocks[0] + [OverTravel,GuideRadius,0],center=false);
	translate([-OverTravel,(Battery.y – KeyBlocks[1].y),0])
	cube(KeyBlocks[1] + [OverTravel,GuideRadius,0],center=false);

	}

	translate([(-OverTravel), // battery top access
	(CaseOffset.y – Protrusion),
	Battery.z])
	cube([CaseSize.x,(CaseSize.y + 2*Protrusion),(TopThick + Protrusion)]);

	translate([(CaseOffset.x – Protrusion), // battery insertion allowance
	(CaseOffset.y – Protrusion),
	Battery.z])
	cube([(CaseSize.x + 2Protrusion),(CaseSize.y + 2Protrusion),(TopThick + Protrusion)]);


	translate([(Battery.x – Protrusion), // remove thumb notch
	(CaseSize.y/2 + CaseOffset.y),
	(ThumbRadius)])
	rotate([90,0,0])
	rotate([0,90,0])
	cylinder(r=ThumbRadius,
	h=(WallThick + GuideRadius + 2*Protrusion),
	$fn=22);

	PinAssembly();

	translate([CaseOffset.x + PinRecess/2 + Protrusion/2,(Contacts[1].y + Contacts[0].y)/2,Contacts[0].z])
	cube([PinRecess + Protrusion,
	(Contacts[1].y – Contacts[0].y + PinFlange[OD]),
	2*PinFlange[OD]],center=true);

	}

	}

	// Lid position offset to match case

	module Lid() {

	translate([-LidSize.x/2 + LidOffset.x + LidOverhang,LidSize.y/2 + LidOffset.y,0])
	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,$fn=8);

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

	cube([LidSize.x/4,0.75LidSize.y,4ThreadThick],center=true); // epoxy recess
	}

	}


	//——————-
	// Build it!

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

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

	if (Layout == "Pins") {
	color("Silver",0.5)
	PinShape();
	PinAssembly();
	}

	if (Layout == "Show") { // reveal pin assembly
	difference() {
	Case();

	translate([(CaseOffset.x – Protrusion),
	Contacts[1].y,
	Contacts[1].z])
	cube([(-CaseOffset.x + Protrusion),
	CaseSize.y,
	(CaseSize.z – Contacts[0].z + Protrusion)]);

	translate([(CaseOffset.x – Protrusion),
	(CaseOffset.y – Protrusion),
	0])
	cube([(-CaseOffset.x + Protrusion),
	Contacts[0].y + Protrusion – CaseOffset.y,
	CaseSize.z]);
	}

	color("Silver",0.15)
	PinAssembly();

	translate([0,0,Battery.z + Gap])
	Lid();
	}

	if (Layout == "Build") {
	translate([-(CaseSize.x/2 + CaseOffset.x),-(CaseOffset.y – BuildOffset),BaseThick])
	Case();
	translate([CaseSize.y/2,(CaseOffset.x/2 – BuildOffset),0])
	rotate([0,0,90])
	Lid();
	}

	if (Layout == "Fit") {
	Case();
	translate([0,0,(Battery.z + Gap)])
	Lid();
	color("Silver",0.25)
	PinAssembly();

	}

view raw NP-BX1 Battery Holder – 1.5mm pins.scad hosted with ❤ by GitHub

2018-11-29

Electrolux Vacuum Cleaner: Cord Protection

The ancient (Came With The House™) Electrolux canister vacuum cleaner long ago lost the plastic bushing around the opening passing its retractable cord, which I’d long sworn to replace. A recent trip around the Basement Laboratory paused near the recently relocated Box o’ Wire Loom & Braid, whereupon I snipped off a few inches of split loom and tucked it in place:

Electrolux Vacuum – cushioned cord cutout

Looks and works better than before, anyhow.

The blue flap dangling off the back should latch over the exhaust port, but failed long ago when the latch tab eroded. I attempted a repair, which never worked quite right, and won’t get around to attempting another for quite a while.

2018-11-27

Tag: Improvements

Astable Multivibrator: SMT LED Ballast Resistor

Desk Drawer Stops

Astable Multivibrator: NP-BX1 Base

Halogen Desk Lamp Conversion

JYE Tech DSO150 Oscilloscope: Battery Power

Sony NP-BX1 Battery Holder: SMT Pogo Pin Contacts

Electrolux Vacuum Cleaner: Cord Protection