Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
As a temporary expedient while awaiting more outlets in the basement, I screwed several hundred watts of LED strip lighting to the floor joists so I could see where I was going:
First pass at basement lighting
The switch seemed to run warm, which I attributed to being snuggled up against one of the LED strips, eventually became intermittent, and finally failed with the lights out.
Prying apart the snapped-together case destroyed it, but that didn’t really matter when I saw the innards:
T8 LED power switch
The “intermittent” action came from the melted post on the switch actuator at the top of the photo. The “warm” came from the barely crimped black wire on the right side of the switch, which *might* have had half a dozen strands caught in the flattened crimp triangles.
I replaced it with an identical switch from the assortment that came with the lamps. That one seems to run cooler, although I doubt the crimps are really up to any reasonable quality standards.
In addition to adding basement outlets & lighting circuits, the rest of the house has some electrical wiring peculiarities; the kitchen microwave really shouldn’t share a circuit with the dining room lights.
It’s apparently customary for piano tuners to annotate their work on the keys, starting after the serial numbers on the bass notes at the left end:
Piano tuner notes
After admiring that, you can pop the hammer links off with a prybar:
Detaching piano keys
All 88 keys stack neatly into a Home Depot Extra Small moving box, filling it about 2/3 full, starting with the bass keys on the bottom:
Boxed piano keys
I harvested the lovely wood panels, then the scrapper hauled the carcass to the transfer station. Perhaps it raised the secret chord when it hit the bottom …
Lest you wonder why we didn’t try to contact X, who would surely be interested in a free piano: we did. Believe me, we tried, for many values of X, only to find nobody wants a piano in this day and age.
Mary’s new Sewing Room (f.k.a. The Living Room) has a set of cellular blinds over the windows:
Sewing Room – Cellular shades
They have internal springs instead of pull cords: you just grab the tabs on the lower bar to raise / lower the shade. This worked with one hand for the narrower shades on the sides, but the center shade seemed unusually difficult to move, even with one person on each end.
Then, one morning, the center shade jammed in place about halfway up and resisted all persuasion to move in either direction. So I evacuated all the plants, dismounted the shade, laid it out on the quilting table, and found a sticker showing they were manufactured in 2018:
Cellular shade – data plate
They were surely installed shortly thereafter, so they’re the better part of six years old. Although parts are available for some shades, casual searching suggested replacing all three blinds (because color matching) would require more attention than I wanted to apply in the midst of our ongoing real estate transactions.
Gingerly removing the spring released the tension on the mechanism and a vast array of cords, so I could lay things out and see how the shade was supposed to work:
Cellular shade – cord layout
Four cords support the lower bar, pass through the entire height of the shade, and emerge through plastic guides into the upper bar:
Cellular shade – grommet
All four cords pass around pulleys in the fixed block on the left, to more pulleys in the movable block on the right, then back to the fixed block where they are tied off:
Cellular shade – cord snag
The possibility of successfully re-stringing those cords from a cold start is exactly zero, so I knew I must not fumble anything.
The hook on the right side of the movable block connects to the spring counterbalancing the weight of the shade:
Cellular shade – block missing cord
After considerable pondering, I noticed the upper pulley has four cords on its outer side and the lower pulley has only three. Reasoning by symmetry, I concluded that can’t possibly be right.
Gentle poking at the fixed block showed where the missing cord went:
Cellular shade – errant cord
Apparently the loop slipped off the lower pulley in the movable block, distributed several feet of loose cord somewhere inside the shade, and eventually bound tight around the lower pulley in the fixed block.
Removing the cover from the fixed block confirmed the diagnosis:
Cellular shade – fixed block disassembly
Removing the cover from the movable block shows the cord layout, with the lower pulley still missing one loop:
Cellular shade – block cord layout
Gingerly pulling the loose cord from deep inside the shade, I managed to extend the errant loop back around the pulley in the movable block, then, following the “First, do no harm” part of the Hippocratic Oath, I immobilized all the cords in their current positions relative to all the pulleys / pins / blocks:
Cellular shade – block cords sorted
Which revealed how the cord got loose in the first place:
Cellular shade – block side view
Apparently half a dozen years is enough to warp a thin plastic plate. Who would have expected that?
With the cords sorted out, I eased them off the pulleys, freed the block, and discovered the situation was worse than I thought:
Cellular shade – block warp
Now that I knew what to look for, it was obvious the tiny pin molded into the boss supporting the lower pulley had broken, allowing the cord to slide between the pulley and the top plate. You can see the dark hole vacated by the pin in the first picture of the upper block.
Knowing what I had to do next, I snipped the pin off the other boss with flush-cutting pliers.
Line up the drill press using the top plate to center the drill in the boss, drill a hole suitable for a small screw, and repeat for the other pulley:
Cellular shade – block drilling
At that point, the New Basement Shop™ consisted of empty shelves and full moving boxes, but the drill press and tool chests were accessible. The basement has four outlets, one in each far-distant corner, but I have extension cords and know how to use them; I intend to spray-paint the walls with outlets in the near future.
With the holes drilled, I restored the pulleys / pins / cords to their proper locations:
Cellular shade – cord sorting
Almost proper, as it turned out I put the errant loop on backwards, so I had to go through one completely assembly / test / disassembly cycle.
The two new screws in the pulleys, in addition to the two old screws along the midline, hold the top plate flat against the bottom plate, with the remaining pins seated securely in their holes.
Reassemble in reverse order, tension the spring, snap it on the movable block, and reinstall in the window. I don’t have any pix of the completed assembly, but the shade now works as it should: we can raise and lower it from either end with just a bit of effort.
So I bought a packing tape dispenser (“gun”) for the 4 inch wide clear tape over the box labels, only to find the frame projected beyond the rubber roller on one side:
Packing tape dispenser – projecting edge
That steel flange prevented the roller from making firm contact with the box and pressing the tape into place. I’d never seen such a thing on any of the other tape guns I’d used, including a similar one (for 2 inch tape) on loan from the good folks at archive.org:
Packing tape dispensers
Well, even with the shop in disarray, I can fix that:
Packing tape dispenser – filed edge
Filing that bump down definitely improved my disposition over the next few hundred boxes …
Nuheara predicts two to three years of battery lifetime for their IQbuds² MAX not-really-hearing-aids and, indeed, after 2-½ years of more-or-less steady use, the right bud developed a bad case of not charging fully and discharging quickly. The batteries are not, of course, customer-replaceable, so one can:
Buy a single bud
Buy a complete new pair + case + accessories
Ask about their repair service
Unsurprisingly, a single bud costs more than half the cost of the full set and the repair service is a complete mystery. Given that the left bud’s battery will likely fail in short order, let’s find out what’s inside.
Your ear sees this side:
Nuheara IQbud – bottom view
The dark oval is a (probably IR) sensor telling the bud when it’s jammed in your ear.
Everybody else sees this side:
Nuheara IQbud – top view
The small slit over on the right and the two holes around the top seem to be for various microphones.
Jamming a plastic razor blade into the junction between the two parts of the case, just under the mic slit, and gently prying around the perimeter eventually forces the adhesive apart:
Nuheara IQbud – case splitting
Do not attempt to yank the two pieces apart, because a ribbon cable joins the lower and upper PCBs:
Nuheara IQbud – ribbon cable
The metallic disk in the lower part is the lithium battery.
Ease the upper part away, being very careful about not tugging on the ribbon cable:
Nuheara IQbud – raising battery
The battery has moved upward, revealing the lower PCB.
Rolling the upper part toward the ribbon cable eventually produces enough space to extract the battery:
Nuheara IQbud – battery freed
Note the orientation:
The rebated end is the negative terminal and faces outward
The wider end is the positive terminal and faces inward
With the battery out, you can admire the PCBs and ribbon cable:
Nuheara IQbud – interior view
What is not obvious from the picture: two pairs of spring-loaded pogo pins contacting the battery. There is no actual battery holder, as it’s just tucked into the structure of the bud, with the perimeter adhesive providing the restraining force for the pogo pins.
The 1654 cells I got came with wire leads welded to the cell and a complete Kapton enclosure; apparently other devices use soldered connections rather than pins. They proudly proclaim their “Varta” heritage, but I have no way to prove they actually came from Germany.
I snipped off the wires, carved a pair of holes through their Kapton for the contact pins, tucked the cell in the bud, pressed the halves together, applied a clamp, then wrapped a strip of Kapton tape around the perimeter:
Nuheara IQbud – reassembled
It seems remarkably easy to wrap the tape over the front microphone, but don’t do that. Conversely, sealing the entire perimeter is the only way to prevent acoustic feedback, so I added a snippet of tape just under the front mic opening.
Do that for the other bud and declare victory.
That is, fer shure, not the most stylin’ repair you’ve ever seen, but I was (for what should be obvious reasons) reluctant to glue the halves together. I expect the tape to peel off / lose traction after a while, but I have plenty of tape at the ready. Worst case, I can glop some adhesive in there and hope for the best.
Because the buds lost power during their adventure, they required a trip through their charging case to wake them up again. After that, they work as well as they did before, with consistently longer run time from both buds.
While pondering what to do with the shattered kitchen scale, I got a bottom-dollar replacement touting its rechargeable lithium battery. After giving it the obligatory charge-before-using, I put it in service. Five days later, its battery was dead flat discharged.
So I gutted it to extract the battery:
Cheap digital scale – lithium cell
It’s a cute little thing, isn’t it?
Much to my surprise, the obligatory battery rundown test showed it matches its 0.74 W·hr label:
Kitchen Scale – Charge1
We all know where this is going, right?
Crunche a connector on the battery, another on the scale, and make up a suitable current tap for a meter:
Cheap digital scale – current measurement setup
Which looked like this:
Cheap digital scale – active current
That’s about what I found for the craptastic scale running from a pair of CR2032 primary cells, so it’s not out of line.
Turn off the scale and measure the idle current:
Cheap digital scale – inactive current
Do you think I got a dud?
For all I know, the little microcontroller under the epoxy blob is running a continuous attack on my WiFi network, with the intent of siphoning off all my sensitive bits. Ya never know.
Dividing the battery’s 200 mA·hr rating by 4 mA says it really should be dead in 50 hours, which is close enough to five days: diagnosis confirmed!
Rather than fight, I switched to a battery with more capacity:
Cheap digital scale – NP-BX1 replacement
It’s long past its prime, but ought to last for a month, which is about as long as the shattered scale survived on a similar battery.
I suppose this is a consequence of being able to get two eyeglasses + two sunglasses in three different frame styles and two different prescriptions, each with progressive lenses and antireflective coating, for about $350 delivered halfway around the planet.
The Smell of Molten Projects in the Morning 