Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
Although it’s technically sandpaper, the effect is more like lapping than sanding and the O-rings now ride on a very smooth surface.
The knurled half-ring is ¼-inch = 6.3 mm acrylic with an ID precisely fitting the pillar + sandpaper:
Sink O-ring seat polishers
The one on the right has an OD matching the surface inside the spout, but it turned out to be easier using fingertips, even if that isn’t quite how one should do lapping.
The LightBurn layout shows the “knurls” are half-circles either added or subtracted from the arcs, as LightBurn’s Circular Array tool is my copilot:
O-ring Polishers – LB layout
You’ll want to measure the ID and OD of your sink faucet, as well as the thickness of your sandpaper, before making make your own.
Imagining / laying out / building those took less time than writing this up; I loves me some quick laser cutter action.
Until a month or two ago, when it began disconnecting randomly.
The camera cable has a standard USB A connector on one end and what looks like a 1.5 mm JST ZH connector on the other:
Laser cutter camera cable
Of course, it’s not quite long enough, so it plugs into a good-quality 1 meter USB 3.0 extender to the PC sitting atop the laser cabinet.
Some low-effort tweaks were unavailing:
Different USB ports
Different USB extension cable to the ports
Hub vs. direct
Eventually, some rummaging in the Box o’ USB Cables produced a cable from a different camera and, as you might expect, swapping the two identical cables solved the problem.
I have no idea what’s going on, but I’d lay significant money that when this cable gets flaky, swapping the original cable back in will solve the problem once again.
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.
The Moonlander keyboard has per-key LEDs that I’ve denatured enough that most show a pale gray, with a few others highlighted in orange. A few weeks ago the LEDs on the right-hand thumb cluster and the N key went nuts, cycling through a surprising assortment before settling on bright red; the obvious resets / firmware reflashing / tapping were all unavailing.
ZSA’s tech support recommended taking the thumb cluster apart to check the ribbon cable connecting it to the main keyboard half:
Moonlander thumb cluster – PCB bottom
Come to find out my unclean personal habits lodged a particularly corrosive nugget of board chow on the cable:
Moonlander – corroded ribbon cable
It’s a more-or-less standard 0.5 mm pitch cable, but only 20-ish mm long, much shorter than the cables carried by the usual sources. ZSA sells them for $2 each, plus $25 courier shipping, so I bought three; they arrived in two days from halfway around the planet.
Because I don’t foresee my personal habits changing any time soon, I tucked a Kapton tape snippet in the gap to serve as a gutter:
Moonlander thumb cluster – tape shield installation
That’s with the two hinge screws out and the cluster eased down-and-away from the keyboard enough to get the tape pressed against the keyboard.
With the screws installed and the cluster at its normal most-downward angle, the gutter closes up:
Moonlander thumb cluster – tape shield folded
With the cluster in its normal operating position (for me, anyway), the gutter is nearly invisible:
Moonlander thumb cluster – normal position
For the record, I tucked the remaining ribbon cables inside the left-hand thumb cluster against future need.
After about five and a half years, the OEM shift indicator in my rear SRAM Grip Shift failed, so I replaced it with a piece of right-angle polypropylene backed with hot pink vinyl:
All done by hand, because it’s easy.
I’d used up my stock of genuine replacement indicators long ago, but they’re now down to two bucks (probably because Grip Shifters are obsolete) and I’ve stocked up in anticipation of future need.
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.
The pebble caught in this crater has worn flat on the outside and started cutting through the tire carcass into the tube:
Schwalbe Marathon Plus – Stone gash
Gotta love those Marathon Plus tires!
So my bike now has a new tire, tube, and rim on the back.
The old spokes looked OK and tightened up without incident. For the record, the Park TM-1 tension meter puts the drive-side spokes at 25 and the other side just under 20, with the total runout & wobble under a millimeter.
Having now replaced all four rims on our bikes over the course of two years, I sawed the three rims still awaiting recycling into samples:
Tour Easy – 30 k mile rim wear
Unlike contemporary bikes, our Tour Easy recumbents have rim brakes and those original rims are pretty well worn out; they’re not supposed to be concave like that.
The Smell of Molten Projects in the Morning 