Category: Electronics Workbench

Electrical & Electronic gadgets

HQ Sixteen: Improved Control Cap Final Assembly

My version of the Handi-Quilter HQ Sixteen grip control caps requires some assembly:

Control Button Caps – solid model – build view

Getting the OEM caps off the handlebars required carefully applying torque through a strap wrench, but they eventually came free:

HQ Sixteen – OEM grip cap – screw holes

I don’t know what the unused screw hole between the two gnarly holes was for; perhaps they discovered one hole was inadequate.

The alert reader will note the two screw holes are not the same distance from the end of the tube, which required rebuilding the plug model to match:

Control Button Caps – solid model – plug holes

Which is why I didn’t glue the plug into the cap before I got the OEM caps off.

Redrill the tube holes to 3 mm, file the burrs from both the OEM and my drilling, smooth the edges, and the plug fit perfectly. Then I seated the M3 square nuts behind those hole and, after installing the new plugs in the handlebars, glued the caps in place with a simple fixture to ensure the front faced forward:

– HQ Sixteen – grip cap faceplate gluingHQ Sixteen – grip cap gluing

The clamp gently compresses the foam enough to hold the flats against the bench block while the JB Plastic Bonder cures.

After verifying all the buttons worked, I glued the faceplates to the cap bodies:

HQ Sixteen – grip cap faceplate gluing

The tape held the faceplate in place while I snugged the clamps.

Modulo my weak graphic design skills, the caps look pretty good:

HQ Sixteen – grip cap installed – right

And, after a bit of wiring yet to be described, the buttons do exactly what their legends suggest:

HQ Sixteen – grip cap installed – left

The white sheet with feeble graphics can be peeled off, so I have another chance to tart it up.

The overall idea was to replace the failing Start/Stop switch while duplicating that switch on both caps. While I was at it, I also duplicated the Needle Up/Down button, because who wants asymmetric caps?

Mary is assembling another quilt and the new switches will get plenty of action …

2025-05-01
Power Outage

This housing development was the second in Poughkeepsie to have underground utilities and, to put it mildly, a lot has rotted out over the last 70 years.

Over the weekend, one phase of the AC power flickered and eventually failed completely, with the other phase supplying a steady 120 VAC. Central Hudson (Gas & Electric) crews located long-lost buried boxes in places not matching their maps:

Power Outage – flooded box

Then they pumped / bailed enough water to repair / lengthen the wires:

Power Outage – corroded wiring

I’ve never before seen anybody work on live wires underwater.

They installed above-ground boxes to simplify The Next Time.

Some improvisation was required:

Power Outage – improvised cocoa stirring

Gotta say, cold Fireball Cocoa tastes different than hot Fireball Cocoa.

2025-04-28

HQ Sixteen: Handlebar Control Button Caps

Each of the HQ Sixteen’s handlebars has a cap with control buttons:

HQ Sixteen control caps - side view — HQ Sixteen control caps – side view

The left cap:

HQ Sixteen control caps - left — HQ Sixteen control caps – left

The right cap:

HQ Sixteen control caps - OEM right — HQ Sixteen control caps – OEM right

The membrane switch overlay has textured bumps, although both of us have trouble finding them.

The Start / Stop switch gets the most use and, as you’d expect, has become intermittent after two decades of use.

Mary thinks a Start / Stop switch on both caps would be an improvement, letting her position quilting rulers with her right hand and run the machine with her left hand & thumb. I don’t know how the switches are wired, but the wiring suggests either simple single-bit inputs or a small matrix.

She also finds membrane switches difficult to press, so I’m in the process of replacing the control caps with something more to her liking.

The current concept goes a little something like this:

HQ Sixteen control caps - new caps — HQ Sixteen control caps – new caps

Stipulated: my art hand is weak.

Those are little bitty SMD switches:

HQ Sixteen control caps - new caps overview — HQ Sixteen control caps – new caps overview

They’re easy to locate by touch, with a stem length chosen to “feel right” when pushed.

They have been grievously misapplied:

HQ Sixteen control caps - switches — HQ Sixteen control caps – switches

The solid model has three main pieces and a lock for the ribbon cable:

Control Button Caps - solid model - build view — Control Button Caps – solid model – build view

Those pockets keep the switches oriented while the glue cures.

Two screws through the handlebar secure each cap. Handi-Quilter drove sheet metal screws into their OEM caps, distorting them enough to jam solidly into the handlebars. I’ve been reluctant to apply enough force to loosen them, so they remain frozen in place until the current quilt is done.

The new plugs have recesses for M3 square nuts to make them easily removable. As with the handlebar angle adapters, I’ll glue the plugs into the caps.

A slightly exploded view shows how the pieces fit together:

Control Button Caps - solid model - show view gapped — Control Button Caps – solid model – show view gapped

The switch plate sits recessed into the cap to allow room for the label (about which, more later):

Control Button Caps - solid model - show view assembled — Control Button Caps – solid model – show view assembled

The OpenSCAD source code as a GitHub Gist:

	// Handiquilter HQ Sixteen handlebar control button caps
	// Ed Nisley – KE4ZNU
	// 2025-04-05

	include <BOSL2/std.scad>

	Layout = "Show"; // [Show,Build,Grip,Body,Face,FaceBack,Plug,CableLock]

	// Angle w.r.t. handlebar
	FaceAngle = 30; // [10:45]

	// Separation in Show display
	Gap = 5; // [0:20]

	/* [Hidden] */

	HoleWindage = 0.2;
	Protrusion = 0.1;
	NumSides = 234;

	WallThick = 3.0;

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

	Grip = [19.7,22.4,15.0]; // (7/8)*INCH = 22.2 mm + roughness, LENGTH=OEM insertion depth
	GripRadius = Grip[OD]/2;

	FoamOD = 34.0; // handlebar foam
	FoamRadius = FoamOD/2;

	SwitchBody = [6.3,6.3,4.0]; // does not include SMD leads
	SwitchStemOD = 3.5 + 2*HoleWindage;
	SwitchOC = 10.0; // center-to-center switch spacing
	LabelThick = 0.5; // laminated overlay

	FaceRim = 2.0; // rim around faceplate
	FaceThick = 2.0; // … plate thickness
	FaceDepth = FaceThick + LabelThick; // inset allowing for faceplate label

	CapOD = 38.0; // overall cap diameter
	CapTrim = FoamRadius; // flat trim on front
	CapBase = 5.0; // bottom thickness
	Cap = [FoamOD – FaceRim,CapOD,CapBase + CapOD*tan(FaceAngle)];
	echo(Cap=Cap);

	TargetSize = 4.0; // laser alignment targets
	TargetsOC = [40.0,40.0];

	Cable = [10.0,2.0,WallThick]; // aperture for cable lock

	ScrewAngles = [-45,45]; // mounting screws
	Screw = [2.0,3.0,7.0]; // OEM = sheet metal screw
	ScrewOffset = 6.0; // from top of grip tube

	SquareNut = [3.0,5.5,2.3 + 0.4]; // M3 square nut OD = side, LENGTH + inset allowance
	NutInset = GripRadius – sqrt(pow(GripRadius,2) – pow(SquareNut[OD],2)/4);

	PlugOA = [(Grip[ID] – 2*WallThick),(Grip[ID] – 1.0),(CapBase + ScrewOffset + 10.0)];
	echo(PlugOA=PlugOA);

	//———-
	// Define objects

	//—–
	// Handlebar tube

	module GripTube() {

	difference() {
	tube(3*Grip[LENGTH],GripRadius,Grip[ID]/2,anchor=TOP);
	for (a = ScrewAngles) {
	down(ScrewOffset) zrot(a-90)
	right(GripRadius)
	yrot(90) cylinder(d=Screw[OD],h=Screw[LENGTH],center=true,$fn=6);

	}
	}
	}

	//—–
	// SVG outline of faceplate for laser cuttery

	module FaceShape(Holes=true,Targets=false) {

	difference() {

	scale([1,1/cos(FaceAngle)])
	difference() {
	circle(d=(Cap[OD] – 2*FaceRim),$fn=144);
	fwd(CapTrim – FaceRim)
	square(Cap[OD],anchor=BACK);
	}

	if (Holes)
	for (i=[-1:1]) // arrange switch stem holes
	right(i*SwitchOC)
	zrot(180/8) circle(d=SwitchStemOD,$fn=32);

	}

	if (Targets)
	for (i = [-1,1], j = [-1,1])
	translate([iTargetsOC.x/2,jTargetsOC.y/2])
	square(2.0,center=true);
	}

	//—–
	// Faceplate backing sheet
	// Switch bodies indented into bottom, so flip to build

	module FacePlate(Thick=FaceThick,Holes=true) {

	difference() {
	linear_extrude(height=Thick,convexity=5)
	FaceShape(Holes);
	up(SwitchBody.z/4)
	for (i = [-1:1])
	right(i*SwitchOC)
	cube(SwitchBody,anchor=TOP);
	}
	}


	//—–
	// Cap body

	module CapBody() {

	$fn=48;

	up(CapBase + (Cap[OD]/2)*tan(FaceAngle)) xrot(FaceAngle)
	difference() {
	xrot(-FaceAngle)
	down(CapBase + (Cap[OD]/2)*tan(FaceAngle))
	difference() {
	cylinder(d=Cap[OD],h=Cap[LENGTH]);
	fwd(CapTrim) down(Protrusion)
	cube(2*Cap[LENGTH],anchor=BACK+BOTTOM);
	up(CapBase)
	difference() {
	cylinder(d=Cap[ID],h=Cap[LENGTH]);
	fwd(CapTrim – 2*FaceRim)
	cube(2*Cap[LENGTH],anchor=BACK+BOTTOM);
	}
	down(Protrusion)
	cylinder(d=Grip[ID],h=Cap[LENGTH]);
	}
	cube(2*Cap[OD],anchor=BOTTOM);
	down(FaceDepth)
	FacePlate(FaceDepth + Protrusion,Holes=false);
	}

	}

	//—–
	// Plug going into grip handlebar

	module CapPlug() {

	$fn=48;

	difference() {
	tube(PlugOA[LENGTH],id=PlugOA[ID],od=PlugOA[OD],anchor=BOTTOM)
	position(TOP)
	tube(CapBase,id=PlugOA[ID],od=Grip[ID],anchor=TOP);
	for (a = ScrewAngles)
	up(PlugOA.z – CapBase – ScrewOffset) zrot(a-90)
	right(PlugOA[ID]/2)
	yrot(90) {
	cube([SquareNut[OD],SquareNut[OD],SquareNut[LENGTH] + NutInset],center=true);
	zrot(180/6)
	cylinder(d=(SquareNut[ID] + 2*HoleWindage),h=PlugOA[ID],center=true,$fn=6);
	}
	}

	}

	//—–
	// Lock plate for ribbon cable

	module CableLock() {

	difference() {
	cuboid([2*Cable.x,PlugOA[ID],WallThick],rounding=WallThick/2,anchor=BOTTOM);
	for (j = [-1,1])
	back(j*Cable.y) down(Protrusion)
	cube(Cable + [0,0,2*Protrusion],anchor=BOTTOM);
	}

	}

	//———-
	// Build things

	if (Layout == "Grip") {
	color("Silver",0.5)
	GripTube();
	}

	if (Layout == "Face")
	FaceShape(Targets=true);

	if (Layout == "FaceBack")
	FacePlate();

	if (Layout == "Body")
	CapBody();

	if (Layout == "Plug")
	CapPlug();

	if (Layout == "CableLock")
	CableLock();

	if (Layout == "Show") {

	color("Green")
	up(CapBase)
	CableLock();

	color("Orange")
	down(Gap)
	down(PlugOA[LENGTH] – CapBase)
	CapPlug();

	color("Cyan",(Gap > 4)? 1.0 : 0.2)
	CapBody();

	color("White",(Gap > 4)? 1.0 : 0.5)
	up(Gapcos(FaceAngle)) fwd(Gapsin(FaceAngle))
	up(CapBase + (Cap[OD]/2)*tan(FaceAngle) – FaceDepth)
	back(FaceDepth*sin(FaceAngle)) xrot(FaceAngle)
	FacePlate();

	down(3*Gap) {
	color("Silver",0.5)
	GripTube();

	down(Gap)
	color("Gray",0.5)
	tube(3*Grip[LENGTH],FoamRadius,Grip[OD]/2,anchor=TOP);
	}
	}

	if (Layout == "Build") {
	right((Gap + Cap[OD])/2)
	CapBody();
	left((Gap + Cap[OD])/2)
	zrot(180) up(FaceThick) xrot(180)
	FacePlate();
	fwd(Gap + Cap[OD])
	up(PlugOA[LENGTH]) xrot(180) zrot(180)
	CapPlug();
	fwd(Cap[OD]/2)
	zrot(90)
	CableLock();
	}

view raw Control Button Caps.scad hosted with ❤ by GitHub

2025-04-18

Wrights SideWinder Bobbin Winder: Laying On Of Hands

Mary attempted to wind a bobbin using the Wrights SideWinder Bobbin Winder she got from a friend:

Sidewinder bobbin winder – top

The URL in the instructions is dead, but the Sidewinder lives on as the Simplicity SideWinder Portable Bobbin Winder:

Simplicity Sidewinder Bobbin Winder

Looks kinda pallid to me, too, although hardcore BarbieCore is also most definitely not our thing.

Anyhow, the motor didn’t even twitch when pressing the button, so after I verified the two AA alkaline cells were Just Fine, I laid it on the Electronics Bench and popped the top to see what was the matter:

Sidewinder bobbin winder – interior wiring

For the record, the red and black wires at the battery compartment are exactly reversed from what you might expect based on, say, the colors of your multimeter probes. I know better, but it comes as a surprise every time.

The pushbutton switch pulls in the relay (red block in the middle), which latches on until the bobbin fills and the accumulated thread lifts the finger riding on the bobbin to rotate the white cam (under the motor), thus opening the switch (black block), releasing the relay, and shutting off the motor.

Which, of course, worked perfectly after I stuck the alkalines back in place on the bench and poked the button to watch the proceedings.

It’s all back together again and continues to run, so I’ll declare victory until the next time she fills a bobbin and, predictably, it doesn’t start.

2025-03-31
LED Strip Lights: Shade Adhesive

This is a quick-and-ugly test to see how well aluminized Mylar will work as a reflective shade for some LED light bars eventually washing the Living / Sewing room ceiling with enough light to brighten the Sewing Table:

LED strip light – Mylar reflector – ugly fit

The key question: how well adhesive adheres Mylar to the pleasantly warm aluminum extrusion serving as the heatsink for 40 W of LEDs:

LED strip light – Mylar reflector – adhesive strips

Perhaps surprisingly, those ½ inch strips come from an A4 sheet by way of a paper cutter.

As with the Mylar shades over the COB LED strips in the laser, the LEDs remain through the aluminized layer:

LED strip light – Mylar reflector – overexposed

The LED bars will be directly visible, so bouncing the direct light against the wall reduces glare and puts it to good use.

The Mylar strips are 1 inch wide, cut with a utility knife against a straightedge, although ⅞ inch seems adequate. The last LED over on the right sits at the endcap, so I will (try to) tuck the Mylar ends under the caps for a cleaner fit.

The bars have two 4 foot strips of LEDs in series, with a lump of circuitry buried in the aluminum extrusion that seems be a bridge rectifier and a small electrolytic capacitor. There’s not nearly enough capacitance to knock down the 120 Hz flicker and I have an uneasy expectation of stroboscopic effects on the sewing machines.

This is a test. […] This is only a test.

Now, to model angle brackets fitting the strips to the window moulding.

2025-03-17
HQ Sixteen: Ball-mounted Stylus Laser
Installing the new ball-mount laser stylus on the HQ Sixteen’s electronics pod required nothing more than two strips of good foam tape:

HQ Sixteen – Stylus Laser – installed – overview

In actual use, you would:
- Lay down a “pantograph” pattern on a paper strip along the rear track under the machine’s carriage
- Position the needle at the appropriate spot on the quilt
- Aim the laser at the corresponding point on the pattern
- Start the machine!
- Move the laser spot along the pattern while the machine stitches that pattern in the quilt
Mary thinks free-motion quilting is easier and I’m not in a position to argue the point.

Anyhow, the key feature of my ball mount is that it’s completely out of the way:

HQ Sixteen – Stylus Laser – installed – front

Which looks comfortingly like the original solid model:

HQ Sixteen – Stylus Laser Mount – solid model – show

Minus the vivid red death ray and pew! pew! pew!

Power comes from a barrel jack in the back intended for the original stylus laser; all small lasers, unless otherwise noted, run from 5 VDC. The jack is 3.5×1.3 mm, but the Drawer o’ Weird Barrel Plugs disgorged a matching right-angle plug. Unsurprisingly, such things are readily available these days.

Splice the laser leads to the plug and cover the evidence with a braided loom + heatshrink tubing:

HQ Sixteen – Stylus Laser – installed – rear

I considered a switch, but the anticipated low duty cycle suggested just unplugging it, so that’s that.

And It Just Worked™.

The backstory begins There and continues to now.
2025-03-03
Ooma Telo2: Speaker2 Failure

After not quite six years, the replacement speaker I hacked into our Ooma Telo2 VOIP gadget failed:

Ooma Telo 2 – replacement speaker installed

Quite by coincidence, a few days earlier a friend reported the speaker in her Ooma Telo2 had failed. This seems to be a common failure mode, with the rest of the gadget continuing to work fine.

The failed speaker showed continuity through its coil and, in fact, still had the same 8 Ω DC resistance as an identical speaker pulled from the Drawer o’ Small Speakers. It did not, however, make a sound when connected to a signal generator, where the new speaker squeaked happily.

So it seems the speaker failed by a mechanical jam, rather than an electrical / wiring failure. It’s not as though we play thrash metal music through the thing, but apparently the magnet disintegrated:

Samsung speaker magnet disintegration

Yes, the coil gap is full of nicely oriented magnetic particles:

Samsung speaker magnet disintegration – detail

If Samsung (or whoever built the speaker) used a poorly sealed neodymium magnet, then it would crumble exactly as shown.

I wonder if that’s how the original speaker failed.

Installing the identical replacement speaker involved more hot melt glue and, as expected, restored the Telo2 to normal operation:

Ooma Telo – second speaker installed

I can do that repair eight more times …

2025-02-24