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.
And kvetching, too
Found in an apartment building lobby:
The LCD gibberish comes from an interaction with the camera shutter. It scrolls a lengthy set of instructions, but the peeling labels demonstrate ain’t nobody got time for that.
You were supposed to figure out how to use this thing with no instructions other than the scrolling display. In particular, the multi-multi-function keypad has no labels.
I suspect most folks just haul out their phones and call the tenant.
The IR sensor on the under-cabinet LED lights I installed half a dozen years ago became increasingly flaky. Its wall wart power supply was on the hot side of uncomfortably warm, so I had an obvious culprit.
The data plate says it’s UL Listed, which is comforting:
The open-circuit output of a 12 VDC power supply should not look like this:
The horizontal scale is 100 ms/div, so those ramps seem much more languid than you might expect from a 60 Hz wall wart.
Adding a 16 Ω load to draw maybe 750 mA got its attention:
The average may be 12 V with too-large dips at the expected 120 Hz, but looky at all the hash riding the output!
No wonder the IR sensor was having such a hard time. When the LEDs are off the voltage ramps between 16 and 5 V. When it eventually turns on the supply has impossible noise levels.
So I cracked the case and extracted the electronics:
Those caps over there on the left rear don’t look healthy, do they?
No. No, they don’t and you shouldn’t be able to see the wiring inside the inductor between them, either.
Probing the Box o’ Wall Warts produced a similar-ish wart that only required harvesting and splicing the teeny coax plug from the failed adapter to put the LED strips back into normal operation.
The identical supply for the identical LED strips on the other side of the kitchen continues to work fine and feel only warm-ish, so I’ll let it be.
Mary’s PT requires a Shoulder Pulley, so I got one that seemed better constructed than the cheapest Amazon crap. In particular, this view suggested the pulley ran on a bearing:
Which turned out to be the case, but, also as expected, the whole thing required a bit of finishing before being put in service.
It’s intended to hang from a strap trapped between an interior door and its frame. The strap was intended to attach to the block (a.k.a. “Thickened base”) through a breathtakingly awkward pair of low-end carabiners:
Which I immediately replaced with a simple, silent, sufficiently strong black nylon cable tie:
Rather than let the metal block clunk against the door, it now sports a pair of cork-surfaced bumper plates:
A doodle of the block dimensions:
Which turned into a simple LightBurn layout:
The blue construction lines represent the actual block & pulley, with the red cut lines offset 2 mm to the outside to ensure the metal stays within the bumpers. It’s possible to pick the block up and whack the pulley against the door, so don’t do that.
Cut out two pieces of 3 mm MDF, two pieces from a cork coaster (covered with blue tape and cut with the paper backing up), peel-n-stick the cork to the MDF, put double-sided foam tape on the block, peel-n-stick the bumpers, then hang on the attic door.
Now it works the way it should!
The LightBurn SVG layout as a GitHub Gist:
A price / coupon scanner in a nearby CVS evidently woke up dead:
Yup, it’s a Linux console boot log, with the last line suggesting something horrible happened inside the device mapper:
A start job is running for dev-mapper-cryptswap1.device
The systemd timing status shows it’s been stuck for a while and has no hope of rescue:
(2d 1h 41min 10s / no limit)
I’d reboot that sucker if it had a keyboard …
Things remained rather quiet at the end of the driveway for a few months, then this happened just before breakfast:
Rt 376 had accumulated some sleet overnight and freezing rain was still falling. The driver apparently lost control around the curve, missed the fire hydrant behind me, and went up the embankment sideways at a pretty good clip.
As far as I can make out, the left front door took out the mailbox post, which was the stump of a utility pole installed long before we bought the property:
Admittedly, the post was rotten around its base, but remained a substantial chunk of wood. The black plastic curl is the air deflector formerly sealing the front of the car’s undercarriage.
Seen from the far end of the debris field, the car smashed dead center into the mighty honeysuckle bush, shed a variety of small parts, recoiled backwards, and tagged the tree as it rolled down the embankment:
The mailboxes sit on the shoulder to the right of the car.
No serious injuries to the driver or passengers, although they got an ambulance ride to the ER to make sure.
Those dents just ain’t gonna buff out:
I did get three years out of the repaired mailbox hinges and perhaps I should preemptively transfer the hardware to the new mailbox.
There’s never a dull moment around here.
A new Dunkin’ opened up about a week ago, whereupon this happened in the right-angled drive-thru lane:
A closer look shows they need more concrete down there:
If that were my gas service, I might have put up two ineffective bollards.
Another specimen at the corner gas station atop their flatbed hauler:
The exposed ICs add a piquant touch, don’t they?
We’ll never know the rest of the story …
The Smell of Molten Projects in the Morning 
