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.
The mandatory warning stickers leave no doubt as to what’s in the box:
You can imagine my relief when the lithium cells arrived intact:
FWIW, the ATK lithium cells arrived in a small box, snugly tucked into a form-fitting foam block:
As long as nothing happens, it doesn’t matter, right?
You’d think Amazon would have learned something from their day in court, though …
The main cicada season has only begun, so these two may have emerged slightly too early:
They’re “ordinary” cicadas, not periodical cicadas, which certainly matters more to them than us.
They’re completely harmless, but definitely don’t look it:
Their topside armor would look great on a robot:
Found ’em dead on the driveway, alas.
We watched a female Monarch Butterfly lay eggs on the stand of milkweed behind the house. She also found a lone plant in the vegetable garden that’s now standing in a vase on the kitchen table where we can keep an eye on the proceedings.
So far, so good:
I never knew Monarch eggs were so elaborate!
Captured with the VGA-resolution USB camera atop the zoom microscope, with VLC applying automagic gamma and level adjustment.
Focus-stacking the three best images helps the ribs toward the leaf, but not by much:
After picking out the images, all of which bear VLC’s auto-generated names like vlcsnap-2017-07-29-09h26m25s720.png, stack them thusly:
align_image_stack -C -a milkweed *png enfuse -o Monarch.jpg milkweed000*
Tinkering with the options might improve things, but … maybe next time.
The tiny lip holding the new LED ring light into the microscope snout lacked enough traction and deposited the ring light on the desk. Having picked up a roll of Scotch Extreme Mounting Tape to see how well it works to attach LEDs to vacuum tubes, I’ll see how well it affixes a ring light to a microscope:
The red plastic film separates the tape layers on the spool; the tape itself consists of incredibly sticky, gooey adhesive on a very flexible foam backing. As you can tell from the ragged edges, cutting it requires some effort, with the adhesive instantly gumming up scissors. I applied a razor knife around the microscope snout’s perimeter, pressing from the red film side and pulling the cut sections apart as I went.
The adhesive exposed on the edges of the roll will glue it to anything it touches, so hang up the roll. Laying it on a shelf will definitely cause heartache & confusion.
The instructions on the back label suggest 2 square inches of tape will hold 1 pound:
Given that the ring light weighs a few ounces, tops, those two strips should do fine.
So my trusty Sony DSC-H5 camera emitted a horrible crunching sound from inside its lens assembly, spat out several error codes which boiled down to “throw me out”, stopped retracting its lens, and developed a nasty rattle. If I thought dropping $2k on a fancy mirrorless DSLR would improve my photography, I’d do it, but instead I picked up a $60 used DSC-H5 from eBay and continued the mission.
Of course, the new-to-me H5 suffers from the half-press switch failure common to that entire line of Sony cameras; my DSC-H1 repair notes still come in handy for many folks.
I’d preemptively repaired the shutter button + switch in my now-defunct H5, so I dismantled it, extracted the control assembly + shutter button, bulldozed the debris aside, dismantled the new(er) H5, transplanted the parts, reassembled it, and declared victory.
Which left me with a pile of parts that could become an H5, if I could fix the lens assembly, which seemed unlikely. While pondering the futility of human existence, I applied a low-effort repair to the defunct shutter button by scuffing the nicely chromed and absurdly tapered tip of the OEM shutter button’s shaft, then applying a dot of JB Kwik epoxy:
The nice sphere came from hanging downward, with the button sitting atop a short brass tube on the workbench.
Filing the dot’s end flat produced a blunt plunger much larger than the OEM tip:
You can just see the edge of the OEM tip inside the grayish end, which puts the filed flat at the original pin’s length.
I punched a new plastic disk to replace the indented one:
Based on past experience, the new plunger tip will work fine, although, unlike the brass screw repair, the OEM plastic pin can still break and launch the spring-loaded shutter button cap into a nearby bush. Given that I may never actually use the repaired button, I’ll take the risk.
Finding out if the new tip will work may take a while:
I did a bit more disassembly than strictly necessary to replace the shutter button, but not by much; you’d be crazy to pay me to fix your camera, fer shure.
A pair of torchiere lamps lit the living room for many, many years:
During their tenure, they’ve gone from 100 W incandescent bulbs to “100 W equivalent” CFL curlicues to “100 W equivalent” warm-white LED bulbs. The LEDs aren’t up to the brightness of the original incandescents, but you can get used to anything if you do it long enough.
After so many years, the plastic shades / diffusers became brittle:
That’s after a bump, not a fall to the floor. So it goes.
Some casual searching didn’t turn up any likely replacements. The shade measures 14 inch = 355 mm across the top, far too large for the M2’s platform, but maybe a smaller shade in natural PETG would work just as well.
ACHTUNG! This is obviously inappropriate for the original incandescent bulbs and would be, IMO, marginal with CFL tubes. Works fine with LEDs. Your mileage may vary.
OpenSCAD to the rescue:
That’s a section down the middle. The top is 180 mm across, leaving 20 mm of general caution on the 200 mm width of the platform. The section above the sharply angled base is 90 mm tall to match the actual LED height, thereby putting them out of my line-of-sight even when standing across the room.
I ran off a short version, corrected the angles and sizes for a better fit, tweaked the thickness to fuse three parallel threads into a semitransparent shell, and …
Producing what looks like thin flowerpot required just shy of seven hours of print time, as it’s almost entirely perimeter, goin’ down slow for best appearance. The weird gold tone comes from the interaction of camera flash with warm-white CFL can lights over the desk.
If you hadn’t met the original, you’d say the new shade grew there:
It’s definitely a Brutalist design, not even attempting to hide its 3D printed origin and glorying in those simple geometric facets.
Those three threads of natural PETG makes a reasonably transparent plate, clear enough that the bulb produced an eye-watering glare through the shade:
So I returned it to the Basement Laboratory, chucked it up in the lathe (where it barely clears the bed), dialed the slowest spindle speed (150 rpm according to the laser tach, faster than I’d prefer), and slathered a thin layer of white-tinted XTC-3D around the inside:
For lack of anything smarter, I mixed 2+ drops of Opaque White with 3.1 g of Part A (resin), added 1.3 g of Part B (Hardener), mixed vigorously, drooled the blob along the middle of the rotating shade, spread it across the width using the mixing stick, smoothed it into a thin layer with a scrap of waxed paper, and ignored it for a few hours.
If the lathe perspective looks a bit weird, it’s perfectly natural: I raised the tailstock end enough to make the lower side of the shade just about horizontal. Given the gooey nature of XTC-3D, it wasn’t going anywhere, but I didn’t want a slingout across the lathe bed.
The lit-up result isn’t photographically different from the previous picture, but in person the epoxy layer produces a much nicer diffused light and no glare.
I might be forced to preemptively replace the other shade, just for symmetry, but we’ll let this one age for a while before jumping to conclusions.
The OpenSCAD source code as a GitHub Gist:
| // Torchiere Lamp Shade | |
| // Ed Nisley KE4ZNU – July 2017 | |
| /* [Build] */ | |
| Section = false; | |
| Shorten = false; | |
| //- Extrusion parameters – must match reality! | |
| /* [Hidden] */ | |
| ThreadThick = 0.25; | |
| ThreadWidth = 0.40; | |
| function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit); | |
| Protrusion = 0.01; | |
| HoleWindage = 0.2; | |
| //- Dimensions | |
| ID = 0; | |
| OD = 1; | |
| LENGTH = 2; | |
| /* [Dimensions] */ | |
| ShadeThick = 1.2; // perpendicular thickness | |
| BaseAngle = 42; // lamp base angle wrt vertical | |
| BaseTopDia = 131.0; // lamp ID at top | |
| ShadeBaseThick = 6*ThreadThick; // horizontal bottom thickness | |
| SeatDepth = 10.0 + ShadeBaseThick; // shade bottom to base top | |
| SeatDia = BaseTopDia – 2* SeatDepth / tan(BaseAngle); // lamp ID at seating depth | |
| ShadeTopDia = 180.0; // top OD, limited by printer platform width | |
| ShadeHeight = 90.0; // height above lamp base | |
| ShadeHoleDia = 36.0; // central hole dia | |
| ShadeAngle = atan(ShadeHeight / ((ShadeTopDia – BaseTopDia)/2)); | |
| echo(str("Shade angle: ",ShadeAngle)); | |
| ShadeHThick = ShadeThick / sin(ShadeAngle); | |
| echo(str(" horiz thickness:",ShadeHThick)); | |
| NumSides = 6*4; | |
| $fn = NumSides; | |
| //- Build it | |
| render(convexity=2) | |
| difference() { | |
| union() { | |
| cylinder(d1=SeatDia,d2=BaseTopDia,h=SeatDepth); // section within lamp base | |
| translate([0,0,SeatDepth]) | |
| cylinder(d1=BaseTopDia,d2=ShadeTopDia,h=ShadeHeight); | |
| } | |
| translate([0,0,SeatDepth]) // inside of upper shade | |
| cylinder(d1=BaseTopDia – 2*ShadeHThick, | |
| d2=ShadeTopDia – 2*ShadeHThick, | |
| h=ShadeHeight + Protrusion); | |
| translate([0,0,ShadeBaseThick]) // seating base | |
| cylinder(d1=SeatDia – 2*ShadeHThick, | |
| d2=BaseTopDia – 2*ShadeHThick, | |
| h=SeatDepth – ShadeBaseThick + Protrusion); | |
| translate([0,0,-Protrusion]) // socket clearance | |
| cylinder(d=ShadeHoleDia,h=2*ShadeHeight); | |
| if (Section) | |
| translate([0,-ShadeTopDia,0]) | |
| cube(2*ShadeTopDia,center=true); | |
| if (Shorten > 0) | |
| translate([0,0,(ShadeTopDia + 2*SeatDepth)]) | |
| cube(2*ShadeTopDia,center=true); | |
| } | |
My “exhibit” at the MHV LUG Mad Science Fair consisted of glowy and blinky LED goodness, with an array of vacuum tubes, bulbs, and the WS2812 and SK6812 test fixtures:
They look much better without a flash, honest. The cut-up cardboard box threw much needed shade; the auditorium has big incandescent can lights directly overhead.
Anyhow, what with one thing and another, the two LED test fixtures spent another few dark and cool days in the Basement Laboratory. When I finally plugged them in, the SK6812 RGBW LED array light up just fine, but three more WS2812 RGB LEDs went toes-up:
That brought the total to about 8 (one looks like it’s working) out of 28: call it a 28% failure rate. While WS2812 LEDs don’t offer much in the way of reliability, running them continuously seems to minimize the carnage.
So I wired around the new deaders and took that picture.
Flushed with success and anxious to get this over with, I sealed the tester in a plastic bag and tossed it in the freezer for a few hours …
Which promptly killed most of the remaining WS2812 chips, to the extent even a protracted session on the Squidwrench Operating Table couldn’t fix it. When I though I had all the deaders bypassed, an LED early in the string would wig out and flip the panel back to pinball panic mode.
It’s not a 100% failure rate, but close enough: they’re dead to me.
As the remaining WS2812 LEDs on the various vacuum tubes and bulbs go bad, I’m replacing them with SK6812 RGBW LEDs.
For whatever it’s worth, freezing the SK6812 tester had no effect: all 25 LEDs lit up perfectly and run fine. Maybe some of those chips will die in a few days, but, to date, they’ve been utterly reliable.
The Smell of Molten Projects in the Morning 