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

Vole Traps: End of Season

A highly effective way to bait a rat trap for garden voles:

Rat trap – still baited

The trap is a Victor M205 (in a 12-pack as M326) with a big yellow plastic bait pedal. The bait is pieces of walnut, secured to the pedal with generous strands of hot melt glue. The trick involves mechanically capturing the walnut by slobbering glue over & around it, forcing the vole to pull & tug while gnawing the last bit of goodness.

Which generally ends badly:

Rat trap – gnawed bait

I do not begrudge the critters a fancy last meal; it’s gotta be better than their usual diet of carrots / radishes / turnips.

Voles have no qualms about eating the bait from a sprung trap with a dead compadre a few millimeters away:

Rat trap – empty bait

They will sometimes eat the walnuts and their dead compadre.

The plastic pedals work much better than the old-style metal pedals at holding the steel arm wire. The wire slides freely on the plastic, in contrast to the previous high-friction metal-on-metal latch.

Some of the traps were entirely too sensitive and required slightly bending the tip of the arm wire upward to increase the friction on the plastic plate. Always always always handle armed traps by the wooden edges beside the kill bar, so when it accidentally snaps your fingers are nowhere near the business end.

After I figured out how to properly bait the traps and we set out half a dozen traps in the most attractive crops, Mary’s garden produced 54 dead voles over the course of 90 days, sometimes in groups of three or four at a time. While this did not prevent all the crop damage, it definitely reduced the problem.

Next year we’ll start early and probably reach triple digits by midsummer.

The same technique with Victor M035 mouse traps (in 12-packs as M035-12) is brutally effective on house mice.

2024-12-06
Quilting Ruler Rack: Expedient Base

Mary is at least the third owner of a steel rack, originally intended to hold packages of retail stuff, which now holds (much of) her collection of quilting rulers:

Quilting Ruler Rack Base – overview

Obviously, it was never intended to hold heavy acrylic sheets, but it worked surprisingly well, right up to the point where too many of the rulers collected on two adjacent columns of pegs and overbalanced the whole affair atop her while she attempted to remove a ruler.

Subsequent accident recreation showed the rack toppled when the weight of the rulers on the two adjacent columns of hooks moved the center of mass outward, just inside the line between those feet, whereupon the slightest tug on a ruler pulled it over.

Measurements revealed the four legs do not sit on a square contact patch, are not parallel to the radii from the center point, and are not uniformly distant from the center. Rather than committing to a finished product, I made a cardboard prototype to verify a bigger base would solve the problem and I could capture all those feet.

You don’t have such a rack, so the exact dimensions don’t matter, but the LightBurn layout looks like this:

Quilting Ruler Rack Base

The disk is two cross-laid sheets for stiffness, with marks burned on the top to help align the feet more-or-less around the center point.

The oblong rings fit around the feet to capture them, so cut eight or twelve to make four stacks a bit taller than the wire diameter.

The H shape then glues atop the rings to hold the feet in place. They’re not removable, but a razor knife will eventually solve that problem.

I slobbered hot melt glue across the cardboard disks to hold them together, glued and aligned the rings where the feet dented the disks, stood the rack in the rings, and glued the H plates.

About an hour elapsed from the sound of the crash to the rack once again standing quietly beside the fabric cabinets.

We’ll run this for a while and eventually replace it with a plywood disk and screwed-in-place clamps for the feet, which will surely call for wood surface preparation / stain / seal treatment.

2024-11-27
Sears Microwave: Laying-On of Hands Repair

Although essentially all kitchens feature a microwave over the stove, essentially all women have difficulty reaching it. As a result, our kitchen has two microwaves: the built-in Samsung over the stove and our trusty Sears Kenmore on the counter.

We’ve had it for a while:

Sears Microwave – data plate

Apart from the turntable rollers, it’s been utterly reliable for the last two decades, until the Start button stopped working:

Sears Microwave – control panel

The membrane switch panel seems to be in good shape, with no cracks in the plastic surface. Only the Start button failed, which suggested the switch contact pad had failed and ruled out broken matrix traces on the flexible circuitry.

Back in the day, they kept casual tinkerers out of the dangerous interior:

Sears Microwave – Torx security screw

That would not be me:

Sears Microwave – security bit set

Over the course of two decades, an occasional food explosion produces a surprising amount of debris:

Sears Microwave – exhaust vent spatter

Go ahead, I dare you, show us your microwave exhaust vent.

The control panel circuit board & wiring looks like this:

Sears Microwave – control board – in place

Unplugging all the connectors proceeds as you’d expect, whereupon a single screw (out of sight to the top) releases the control assembly and pulling the whole thing upward gets it out of the cabinet:

Sears Microwave – control board

The capacitors show no signs of The Plague, but those resistors near the optoisolator (?) in the middle have a suspicious thermal plume.

The ribbon cable from the control surface goes into a connector with the usual locking collar:

Sears Microwave – control panel cable connector

The cable also has cutouts latching into tabs molded into the collar:

Sears Microwave – control panel ribbon cable – locking tabs

Removing two screws at the transformer releases the PCB:

Sears Microwave – control panel interior

Which promptly slammed the whole repair mission to a dead stop: with the entire membrane switch assembly glued to the front of the plastic shell, there is no way to get to the Start switch. Trying to peel the membrane off will most certainly destroy it.

Because all the other functions still worked, including the Add Minute button, we figured we can eke out a few more years before something else fails or the lack of one button gets intolerably annoying.

I reassembled everything in reverse order, plugged it in, and, while setting the clock, discovered the Start button once again worked perfectly.

It’s a classic laying-on of hands repair: take something apart, replace nothing, reassemble, and it works!

If the Start button is not part of the overall switch matrix, with a separate conductor through the ribbon cable, un- and re- plugging would be enough to restore a flaky contact. We’ll never know the rest of the story, although with this post as a reminder, maybe I can remember to tear the matrix apart when we scrap it out.

Somebody give me an Amen!

2024-11-25
Sonicare E5000 Toothbrush + Norelco T770 Beard Trimmer: Final Final Batteries

Although replacing the Sonicare E5000 battery six years ago was supposed to be the last time I’d do that, the poor thing died leaving most of a year’s supply of brush heads in the drawer.

Half a quartet of NiMH AA cells should keep it happy while using up that stash:

Sonicare Toothbrush – NiMH AA cells installed

The AA cells sit at a jaunty angle due to re-re-using the original contact tabs soldered into the PCB.

I’m getting pretty good at taping the case closed:

Sonicare Toothbrush – Kapton tape

Although I have no pictures to prove it, the other half of the AA cell quartet restored youthful vigor to the Norelco T770 beard trimmer. Having interior pictures made finding and popping its case latches so much easier.

If only I could change my batteries that easily …

2024-11-22
Roof Rake

If they think you’re crude, go technical; if they think you’re technical, go crude. I’m a very technical boy. So I decided to get as crude as possible. These days, thought, you have to be pretty technical before you can even aspire to crudeness.
William Gibson — Johnny Mnemonic

Now that the trees have shed most of their leaves / needles, it’s time to get the accumulation off the roof edges. Fortunately, the upstairs windows overlook the biggest piles and, after I considered and rapidly rejected the notion of using the wind stick, Mary convinced me a roof rake would suffice by deploying a too-short broom.

After considering and rejecting several decreasingly elaborate variations of 3D-printed pole-to-pusher-plate adapter nonsense that almost involved our pole saw, this happened:

Roof Rake – in use

The wood pole comes from a left-behind assortment atop the garage’s open ceiling joists and the pusher plate comes from the cardboard box treasure trove.

A laser cutter makes close-fitting rings and hot-melt glue sticks those plates together with gleeful abandon:

Roof Rake – detail

The blue-and-white cardboard plate consists of two box flaps glued together, the glued-up stack of half a dozen rings transfers the torque from the plate to the pole, and the whole affair took the better part of fifteen minutes from idea to cool-enough glue.

It’s back on the garage joists for next year, unless we decide that pole has a higher purpose in life. Worst case, it loses two inches of length.

Bonus: Chore accomplished before the predicted weekend snowfall!

2024-11-21
Sears Sewing Table: Caster Pads

Mary’s much-improved / -repaired Sears Sewing Table wanted to move around on the wood floor in the Sewing Room, so I captured its casters in little pads:

Sears Sewing Table caster pad – installed

A layer of 1 mm cork with PSA adhesive provides griptivity against the floor, a solid layer of 3 mm plywood spreads the wheel force over the cork, and a top ring of 3 mm plywood captures the wheel.

Which looked like this during gluing:

Sears Sewing Table caster pad – gluing fixtures

The scrap on the left served to align cork & plywood; it came from the plywood contributing the shapes. The ring around the cork is a glued-up pair of plywood rings (4 mm wide, outset from the perimeter of the pads) serving to align the two plywood layers.

Verily: time spent making a fixture is never wasted!

And having a laser cutter makes fixtures trivially easy, at least for simple fixtures like those.

2024-11-18
Credit Card Fraud Puzzle

OK, this was different.

A flurry of alerts informed us about charges on an “inactive” credit card account: someone started using my card from a joint account with Mary. Our two cards have different numbers and security codes, although they produce charges to the same account.

The account was inactive for a simple reason: I’d never taken my card out of its mailer and never bought anything with that number. It was activated when Mary turned on her card, although it still carries that sticker:

Invalidated credit card

The customer service agent discovered Amazon had already issued a refund, so apparently the transaction tripped their fraud monitors.

He canceled that number and I’ll get another card, which I intend to continue not using, in a few days.

What I do not understand: how did my card number and security code end up in play, given that I never used it? AFAICT, the only two places that number appears are on the card and in the issuer’s database.

Do you know how such things work?

A casual web search for the (now invalidated) credit card number produces no hits. The simplest explanation: search engines don’t return results for sixteen digits resembling a credit card number.

Verily: just because you’re not paranoid doesn’t mean they’re not out to get ya!

2024-11-15