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.

Category: Home Ec

Things around the home & hearth

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
Price Scanner FAIL: Plausible Deniability

I always suspect there’s a reason behind a missing price label on a shelf, so I waved a half-gallon of milk under a nearby price scanner:

Shop-Rite Scanner FAIL

If you’re thinking that white rectangle doesn’t look like a price, you’re right:

Shop-Rite Scanner FAIL – Warning pop-up

A 10 digit Phone number?

I’m don’t know what a “PPC number” is, although the UPC on the milk carton seems perfectly normal:

Shop-Rite Scanner FAIL – offending bar code

Admittedly, the number starts with a zero and has 12 digits, so it’s definitely not what the price scanner wants. On the other paw, why is a price scanner not looking for a UPC?

The placard below the display is amusing:

Shop-Rite Scanner FAIL – DCNY Requiring Scanner Accuracy

Gray’s variant of Hanlon’s Razor: “Any sufficiently advanced incompetence is indistinguishable from malice.”

No, I neither asked why the scanners didn’t work nor made a phone call, as I’m old enough to know better.

2025-03-14
HQ Sixteen: Crud on the Tracks

Having devoted considerable effort to smoothing the HQ Sixteen’s path across the table, with commensurate improvement, Mary reported the machine suddenly developed a severe hitch in its left-to-right git-along. Given that she is moving fifty pounds of machine with fingertip pressure, anything interrupting its progress is a problem.

We found a spot where the machine abruptly and repeatably stopped rolling, but none of the four wheels had a visible problem and both tracks were smooth. The stitch regulator wheel sat directly above a table surface joint on the track base, but lifting it didn’t change the glitch. Rolling the machine while lifting the rear wheels off the track, which is significantly more difficult than it may seem, still encountered the bump.

Rolling while lifting the front wheels went smoothly, so something was wrong with one of the front wheels. I put the machine back at the worst spot, marked the bottom of both wheel rims, lifted-and-rotated the left wheel half a turn, and found the glitch happened with the right wheel’s mark downward.

I lifted the machine off the carriage, took the carriage to the Basement Shop, and discovered what we could not see in situ:

HQ Sixteen – wheel crud – detail

For scale, the wheels are 8 mm across the flanges.

That thing looks like this up close:

HQ Sixteen – wheel crud – detail

The fibers were almost invisible in my palm as I carried it upstairs to show it off.

Apparently, a few millimeters of plastic fiber dropped from space directly onto the track and got mashed into the wheel as it rolled along. Given the vast expanses of fabric & batting going into projects on a long-arm sewing machine, that crud could have come from anywhere.

As we now realize just how much trouble can come from a tiny bit of crud, finding the next hitch in the git-along will be easier.

2025-03-10
Trivial Laser Projects

A nubbly knob on the M4 screws securing the honeycomb to the laser’s platform:

Honeycomb screw knob

Leveling feet for the HQ Sixteen long-arm machine’s table for the high side of the floor:

HQ Sixteen – table leg leveler – short

And 12 mm taller on the low side:

HQ Sixteen – table leg leveler – tall

Both of those “projects”, which may be too grand a term, went from “I need a thing” to having one in hand over the course of a few minutes yesterday. Neither required a great deal of thought, having previously worked out the proper speed / power settings to cut 3 mm MDF and 1 mm cork.

Other folks may lead you to believe lasers are all about fancy artwork and elaborate finished products. Being the type of guy who mostly fixes things, I’d say lasers are all about making small and generally simple parts, when and where they’re needed, to solve a problem nobody else has.

Perhaps I should devote more attention to using fancy wood with a hand-rubbed wax finish, but MDF fills my simple needs.

With a laser and a 3D printer, shop tools have definitely improved since the Bad Old Days!

2025-03-06
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
Drive Wheelchair Foot Rest Lubrication

After few days in the Drive Blue Streak wheelchair, I finally lubricated the foot rest pivots:

Drive wheelchair foot rest lubrication

The complex molded rests gripped their metal tubes so tightly as be nearly immovable, but one drop of Kroil at the four obvious spots let them turn much more easily.

The flange overlapping the upright tube along the bottom of the picture hits the short protrusion and holds the rest parallel to the floor. A screw at the plastic cap near the top keeps the rests from working their way too far from the upright tube.

I can make it to the Basement Shop™ and back, paying careful attention to detail.

2025-02-17
HQ Sixteen: Handi Feet Conversion

Mary wanted a Ruler Foot (a.k.a. Handi Feet Sure Foot) on her Handi Quilter HQ Sixteen sewing machine, which required removing the original foot, installing the Handi Feet Conversion Kit, then adjusting the foot height above the needle plate:

HQ Sixteen Handi-feet conversion – Sure-foot installed

The Conversion Kit instructions repeatedly recommend hauling the machine to your local Handi Quilter authorized dealer / repair center, which would be an hour’s drive away. Suffice it to say I’m both authorized by a suitable authority and a dab hand with a hex wrench: I can do this thing.

The original foot is a welded assembly with an M5×0.8 screw thread matching the leftmost (darker) rod on the machine:

HQ Sixteen Handi-feet conversion – original foot

It’s sitting atop the label of the Sure Foot kit with a picture of the ruler foot.

Although the instructions suggest you can install the conversion kit without removing the machine cover, I wanted to see what was going on in there and verify everything fit properly:

HQ Sixteen Handi-feet conversion – foot rod clamp

As above, the foot / adapter screws into the left rod, with the rectangular aluminum clamp attached to the follower riding the cam near the top of the machine. The rod slides on the greasy pin absorbing the torque from the follower.

I had to loosen the clamp, slide the rod upward, unscrew the original foot, install the adapter, adjust the rod position for the proper 0.5 mm spacing between ruler foot and the needle plate at bottom dead center, then tighten the screw. The disturbed grease above the block reveals I moved the rod upward about 8 mm through that block during the process; it now sits lower, just a few millimeters above where the factory tech assembled it for the original foot.

The top photo shows half a dozen threads between the top of the adapter and the bottom of the jam nut. Without adjusting the rod position in the clamp, the adapter screw threads are the only way to adjust the foot-to-plate space: each full turn moves the foot 0.8 mm. I screwed the adapter completely into the rod, then backed it out three turns to leave enough adjustment for other feet and fabrics.

The machine cover has a hole providing access to the clamp screw, so, in principle, you can stick a hex wrench in there to loosen / tighten the clamp while making fine adjustments in the foot position, all without removing the cover. If one full turn of the adapter doesn’t set the right position, I highly recommend removing the machine cover to see what you’re doing.

We then installed the Ruler Base on the machine, which required removing the preinstalled Medium fuzzy spacer strips, and all’s well that ends well.

2025-02-12