Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
Much to my astonishment, the ordinary adhesive tape holding the Sonicare Essence power toothbrush together lasted for a bit over a year. As the tape splits along the gap in the case, the coil driving the brush head begins vibrating inside its nest, making a truly horrendous racket.
The new fix looks a bit odd, but works fine:
Sonicare Essence – red tape
The tape comes from Mad Phil’s stash and is, I think, splicing tape for reel-to-reel 1/4 inch recording tape: it has zero stretch, infinite strength, and adhesive that’s obviously lasted forever. The inside of the spool says “NOPI Made in Germany”, which doesn’t lead anywhere useful, although the NOPI name does seem to appear in a tape context.
After a year, the replacement NiMH cells are doing fine, still operating about once a day for three weeks from a 24 hour charge.
The big rectangle at the top will heatsink the main p-MOSFET power switch, which shouldn’t dissipate much power at all. The two lower rectangles heatsink the n-MOSFETs, although I think they may each require a stand-up metal tab to handle the dissipation during high-duty-cycle blinkiness.
The silver line around the edge is soldered copper foil tape connecting the top and bottom ground planes; a dozen or so additional Z wires will connect the planes at high current nodes. It’ll get a bunch of flying signal wires, too, because I’m not a fanatic gotta-embed-all-the-wires kind of guy on stuff like this.
The PCB is 30 mil FR4, which (once again, I make this mistake over and over again) seems a bit bendy for surface-mount parts; I must print a simple nest to stabilize the poor thing. Some of the drilled holes look white, because I hadn’t rinsed out the remains of the silver plating powder; the surfaces are a lot more silvery in person.
Before I etched the back side, I realized I’d made a classic layout blunder: the high-current return path from the center MOSFET flows around the Hall effect sensor near the center of the board. So I filled in the grid pour with a fat point black Sharpie to get more copper in that area:
Hall Effect Brassboard – added etch masking
I think it probably wouldn’t matter either way, but nothing exceeds like excess. FWIW, I use the grid pattern as a way to verify the end of the board etching: when all the holes in the ground pour come clear, all the traces are done, too.
The etched backside came out OK, although with a few etched squares sprinkled in the Sharpie masking:
Hall Effect Brassboard – bare back
The three leads for the Hall effect sensor are just to the right of the center, with the middle lead connected to the ground pour. Given the millivolt-level signals, this isn’t a good place for ground bounce…
It’s etched with ferric chloride, rubbed with a sponge, and took under ten minutes on each side. That’s less than the usual time, which suggests the PCB is plated with half-ounce copper (that’s 0.5 ounce / ft2), rather than the one-ounce copper on the other boards I’ve done recently; just one of the hazards of buying surplus PCB stock. Doesn’t really matter, as the peak currents will be under half an amp and now I know not to use this batch of raw board stock for high current circuits.
All in all, it looks good enough. Now, for some component soldering.
The BOB Yak trailer I tote behind the ‘bent has a flag with a two-part pole which generally stays together; I pull the entire affair out of the frame socket when I hang the trailer up after a trip. The ferrule between the two pole sections recently worked loose and I took it to the Basement Workshop for repair.
The assembled nickel-plated brass (?) ferrule came off both pole sections all too easily, which was a Bad Sign: those little punch marks originally clamped the tubes to the pole. You can’t overestimate the Bad Effects of prolonged vibration on bike parts.
Separating the two ferrule sections required running several pin punches down the bore and tapping gently, all accompanied by considerable muttering; the joint was no longer a slip fit. Eventually I produced this tableau:
BOB Yak trailer flag ferrule
The small hole gauge to the far left showed that the inside of the larger section (on the bottom) had entirely enough clearance for the smaller section, but the rolled ring at its end had somehow shrunk to a tight interference fit.
I’d actually chucked up a piece of rod in the lathe, with the intent of making a mandrel to expand the ring, when I came to my senses. The smaller part was 0.253 inch diameter, so I deployed the letter drills:
an E drill (0.250 inch) just kissed the inside of the ring
an F drill (0.257 inch) opened the ring to a nice sliding fit and still fit easily inside the tube
A few whacks with a center punch reclamped the dimples firmly in place on the dents in the poles.
I carry the Canon SX230HS in my pocket, so as to have a decent camera ready when it’s needed; yes, it’s in a cloth case. Unfortunately, in recent weeks a tiny hair made its way into the lens stack, where it shows up as a slight blurring just left of center in high f/stop images:
Cheap cartridge heater insulation
With the camera attached to the stereo zoom microscope, the hair becomes painfully obvious:
Hair on SX230HX Sensor
Of course it’s in the middle of the image. [sigh]
A bit of searching turns up a bootleg technique to remove the front lens from the turret (basically, just twist and pull), but neither of the internal lens surfaces thus revealed lie near a focal plane and, in any event, were surprisingly clean. The hair is probably lodged just in front of the image sensor, most likely stuck to the back of the final lens where it casts a shadow on the sensor. If it wandered around you’d call it a floater.
Dismantling the entire camera and opening the lens stack seems fraught with peril, particularly as the camera pretty much still works fine for normal picture-taking. More pondering is in order…
Alas, the nice slotted cap I put on the driveway drain can’t handle the amount of debris released by the trees next to the house and above the gutters. I’d removed the thumbscrew to simplify clearing the cap whenever I go for the mail, but that just accentuated the problem:
Driveway drain – fountain
The backup must be over a foot of water at the end of the pipe; that fountain emerges from the 1/4 inch hole for the thumbscrew. Fortunately, the slope is large enough that the water (probably) isn’t backing up into the retaining wall footing drain.
When the pine trees toss their dead needles overboard, the cap plugs solid and, minus the screw, blows across the driveway:
Driveway drain – clogged
It usually doesn’t roll very far, although I’ve retrieved it halfway to the street.
I still think the chipmunks will move in without a grate blocking the pipe, but I’m unsure how to proceed…
Got a call from a friend who was having trouble getting BitDefender to accept its new license key, so I drove over; she’s at the top of a killer hill and I’d already biked my two dozen miles for the day. Solving that problem was straightforward, if you happen to know that they use “authorization” and “license” as synonyms and that you access the key entry dialog by clicking on a text field that doesn’t look at all clickable.
I should have declared victory and returned to the Basement Laboratory, but, no, I had to be a nice guy.
BitDefender kvetched that it had been 777 days since its last scan, so I set up some regularly scheduled scans and automagic updates for everything in sight; we agreed she’d just let the thing run overnight on Mondays to get all that done.
BitDefender also suggested a handful of critical Windows XP updates, plus the usual Adobe Flash and Reader updates, plus some nonsense about Windows Live Messenger that seemed to require downloading and installing a metric shitload of Microsoft Bloatware. Rather than leave all that for next Monday’s unattended update, I unleashed the critical ones, did the Flash and Reader updates, and stuffed the Messenger update back under the rug.
Then AOL recommended an urgent update to AOL Desktop 9.7. She has a couple of AOL email addresses, mostly for historic reasons, and I asked if she ever used the AOL Desktop. She wasn’t sure, so I lit up the installed AOL Desktop 9.6: “Oh, that’s how I get all my email!” OK, so we’ll update that, too.
After all the thrashing was done, the system rebooted and presented us with the single most unhelpful error message I’ve ever seen:
Windows Error – Ordinal Not Found
No, you chowderheads, that is not OK…
Searching on the obvious terms indicated this had something to do with Internet Explorer 8 (remember IE 8?) and produced a number of irrelevant suggestions. The least awful seemed to involve running the Microsoft System File Checker utility:
sfc /scannow
Which I did.
It ran for the better part of an hour, then suggested a reboot. During the shutdown, it replaced 29 files at an average of about 5 minutes per file.
After which, Windows restarted and displayed exactly the same error message. Actually, a series of them; various programs couldn’t locate a fairly wide selection of ordinals in several DLLs.
OK. I give up.
We located a tech who does this sort of thing for a living. I’ve offered to split the cost of getting the box up and running again, with the understanding that it may be easier to start with a fresh off-lease Dell box running Windows 7 than to exhume an aging Windows XP installation.
I stopped caring about Windows toward the end of the last millennium and now keep a Token Windows Box only for hardware like the HOBOWare dataloggers and software like TurboTax.
The horrible paint crazing came from “priming” the bare plywood scrap (yes, that’s a stray hole from its previous life) with a specialty white paint intended for plastic lawn furniture; it apparently gets along poorly with the forget-me-not fluorescent red topcoat. Doesn’t matter in this application and uses up more of both rattlecans, so it’s all good.
Of course, after tucking it in the bike’s underseat bag, I spotted the lost plate along the DCRT: now I have a spare!
The Smell of Molten Projects in the Morning 