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.

Month: August 2016

Leaf Facehugger

T=0.000 s – The dot just below the lower tree branch extending over the middle of the road doesn’t look like much:

Jackson Rd – Leaf Impact – 2016-06-30 – 0337

T=0.600 s – It’s fluttering, which means I’ve noticed it:

Jackson Rd – Leaf Impact – 2016-06-30 – 0373

T=1.317 s – Rolling at just under 20 mph:

Jackson Rd – Leaf Impact – 2016-06-30 – 0416

T=2.117 s – I know exactly what’s going to happen:

Jackson Rd – Leaf Impact – 2016-06-30 – 0464

T=2.850 s – The camera lens is seven inches above my eye level:

Jackson Rd – Leaf Impact – 2016-06-30 – 0508

T=2.867 s – The air stream over the fairing begins tilting the leaf:

Jackson Rd – Leaf Impact – 2016-06-30 – 0509

T=2.883 s – Collision alarm!

Jackson Rd – Leaf Impact – 2016-06-30 – 0510

T=2.900 s – Perfect alignment:

Jackson Rd – Leaf Impact – 2016-06-30 – 0511

T=2.917 s – I’m now riding with an oak leaf plastered over my entire face:

Jackson Rd – Leaf Impact – 2016-06-30 – 0512

I wear big lab-grade splash-resistant goggles over my prescription sunglasses to keep dust out of my eyes: the leaf covers the googles, I can’t see out of my left eye (and, thus, the mirror), and most of my right-eye vision has gone green. Although I managed to not inhale during the impact, the leaf forms a good seal over my nose and mouth.

T=3.683 s – Glancing to the left doesn’t dislodge the leaf:

Jackson Rd – Leaf Impact – 2016-06-30 – 0558

Did you notice the oncoming car?

T=7.483 s – Four seconds later, I’m off the bridge and past the bushes overhanging the guide rail, so I can finally spare a hand:

Jackson Rd – Leaf Impact – 2016-06-30 – 0798

The view to the rear, showing the car that’s been trailing 1 second = 25 feet behind me during this entire adventure:

Jackson Rd – Leaf Impact – 2016-06-30 – rear – 0135

I caught another oak leaf the same way on the rail trail a few weeks earlier at a much lower speed in much less stressful surroundings; I figured that wouldn’t happen again for quite a while.

Ya never know what’s going to happen out there on the road…

2016-08-03
Vacuum Tube LEDs: Brass Ersatz Heatsink

A chunk of 1/2 inch = 12.7 mm brass hex rod looks pretty good as an ersatz heatsink serving as an ersatz plate cap on a halogen bulb standing in for a vacuum tube:

Halogen bulb brass cap – overview

The knockoff Neopixels measure just over 10 mm at their widest points, but some judicious filing rounded it off and brought it down to fit in the 3/8 inch = 0.375 = 9.52 mm hole I drilled in the hex:

Halogen bulb brass cap – wiring

I let it run for a day like that to make sure the thing wasn’t going to crap out, then epoxied everything in place. If the WS2812B controller fails, the repair will require drilling out all the electronics and wiring, then rebuilding it in place.

The fins come from the same HSS cutoff tool I used for the Bowl o’ Fire cap, cut at 2.5 mm intervals to produce 0.9 mm fins that IMO better suit the smaller diameter. I stopped cutting when the tool got through the hex flats to produce a continuous ring, cut the hex off a bit above the top fin, rounded the end with a carbide insert cutting tool, then sanded the flats to shine ’em up a bit:

Halogen bulb brass cap – detail flash

It turns out that 12 inches of wire inside PET braid barely reaches from the cap to the Arduino Pro Mini in the base:

Halogen bulb brass cap – Arduino Pro Mini

Next time, I’m going to add half a foot more wire than I think it can possibly require, with PET braid to suit.

A thin ring of clear epoxy holds the “heatsink” at the dead center of the bulb. It lights up a bit more than I expected, so opaque epoxy may be in order:

Halogen bulb brass cap – detail red

It’s still too big to suit even the big 21HB5A tubes, but brass definitely wins over plastic!

That blue PETG base has become the least-attractive part of the lamp, but it’s survivable for now.

It runs the same TubeMood firmware as the Bowl o’ Fire.

2016-08-02
Monthly Science: Silica Gel Regeneration In Bags

Just for the record, heating four 500 g bags of silica gel at 230 °F for 12 hours overnight works exactly the way it should. Two of the bags baked down to 490 g, another was at 509 g, and the fourth had bulldog clips (rather than staples); given that they started with a measured 500 g of beads, that’s entirely good enough.

Memo to Self: don’t try to cut corners: heat the silica gel packs above water’s boiling point, let them cook overnight, don’t worry about wrecking the weird ground-cloth landscaping bags, and be done with it.

2016-08-01