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.

Category: Science

If you measure something often enough, it becomes science

Sandisk Extreme Pro MicroSD Card: End of Life?

The Sandisk Extreme Pro 64 GB MicroSD card in the Sony HDR-AS30V died on the road once more, got reformatted, worked OK for a while, then kicked out catastrophic I/O errors after being mounted, so I swapped in the High Endurance card:

Sandisk – 64 GB MicroSDXC cards

The Extreme Pro still passes the f3probe tests, so it’s not completely dead, but if I can’t trust it in the helmet camera, it’s dead to me.

It survived 17 months of more-or-less continuous use, although we didn’t do nearly enough riding for three months early this year. Call it 14 months x five rides / week x 1 hour / ride = 300 hours of recording. Multiply by 4 GB / 22.75 minutes to get 3 TB of video, about 50 times its total capacity.

The never-sufficiently-to-be-damned Sony cards failed after less than 1 TB and 15-ish times capacity, making the Sandisk Extreme Pro much better. However, it’s painfully obvious these cards work better for low-intensity still-image recording, rather than continuous HD video.

Using them as Raspberry Pi “hard drives” surely falls somewhere between still cameras and video, although Octoprint’s video snapshots and streaming media must make ’em sweat.

We’ll see how Sandisk’s High Endurance memory works in precisely the application it’s labeled for.

2017-08-22
Mystery Caterpillars

This being caterpillar season, we put a mystery egg mass on a Swiss Chard leaf into a small container:

Mystery Caterpillar – eggs on Swiss Chard

I think the darker egg was a dud, because two days later they all hatched and ate their egg cases, leaving that one behind:

Mystery Caterpillar – hatched

Mary deported them to the trash, put two on a leaf in an aquarium on the kitchen table, and, eight days later:

Mystery Caterpillar – 8 days

They’ve been chowing down on spare garden greenery; unlike Monarchs, they eat what’s set before them.

One has dark “fur”:

Mystery Caterpillar – black morph

The second is lighter:

Mystery Caterpillar – brown morph

A third caterpillar escaped the trash can apocalypse and also resides in the aquarium, albeit stunted by its ordeal:

Mystery Caterpillar – pale morph

They’re too bristly to be Wooly Bears. I’m sure they’ll turn into nondescript brown moths.

2017-08-20
Monthly Image: Cross-striped Cabbageworm

In the normal course of events, this critter would become an undistinguished brown moth:

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Right now, it’s a two-day-old cross-striped cabbageworm. Its kin are voracious consumers of Brassicacae out in the garden and Mary’s raising it as a show-n-tell exhibit for her Master Gardener compadres; she advised it to not start any long novels.

Taken hand-held with the Pixel XL through a clip-on 10x macro lens.

2017-08-15
Monarch Caterpillar Windshield
The Monarch Butterfly egg produced a teeny caterpillar:

Monarch caterpillar – 3 mm – 2017-08-02

Each time it molts, it eats all of its skin except for the transparent cap over the first body segment:

Monarch Windshield – 2017-08-09

If the rest of the caterpillar were behind the windshield, it’d be feet-upward with its “face” at the top.

The picture comes from a focus-stacked set of microscope images captured with VLC; I turned the positioner’s elevation knob the smallest possible amount between each of 16 images along the 1 mm (-ish) height of the capsule. This magic incantation applies more weight to high-contrast and high-entropy regions:
```
align_image_stack -C -a monarch vlcsnap-2017-08-09-18h4*
enfuse --contrast-weight=0.8 --entropy-weight=0.8 -o Monarch_Windshield.jpg monarch00*
# empty line to reveal underscores in previous line
```
That came out pretty well.
2017-08-12
Canon NB-5L Battery Status

My pocket camera has begun kvetching about a low battery rather more often than before, which suggests the batteries I’ve been using since 2014 have gone beyond their best-used-by date.

This came as no surprise:

Canon NB-5L – 2017-08-05

I re-ran a couple of the batteries to make sure they hadn’t faded away from disuse, which didn’t materially change the results. The lightly used Canon OEM battery continues to lead the, ah, pack.

The camera’s lens capsule accumulated a fair bit of dust from many years in my pocket, which lowers its overall contrast and wrecks the high f/ images produced with the microscope adapter.

2017-08-10
Monarch Butterfly Egg
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:

Monarch Butterfly Egg on Milkweed Leaf – 2017-07-29

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:

Monarch Egg – focus stacked

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.
2017-08-05
Monthly Science: Final WS2812 Failures

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:

MHVLUG Science Fair – Chastain – highres_463020980

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:

WS2812 LED test fixture – more failures

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.

2017-08-01