Monthly Science: Praying Mantis Ootheca

We extracted the Praying Mantis oothecae while clearcutting the decorative grasses bracketing the front door. As far as I can tell, they’re still charged up and ready for use.

The masses resemble rigid foam wrapped around grass stems:

Praying Mantis ootheca - stem side
Praying Mantis ootheca – stem side

It’s a mechanical joint, not an adhesive bond, and the dried stems slide freely through the openings:

Praying Mantis ootheca - bottom
Praying Mantis ootheca – bottom

From one side:

Praying Mantis ootheca - right
Praying Mantis ootheca – right

And the other:

Praying Mantis ootheca - left
Praying Mantis ootheca – left

They’re now tied to stems of the bushes along the front of the house, which (I hope) will resemble what the little ones expect to find when they emerge, whenever they do.

Monthly Image: Albino Squirrel

We’re riding home with groceries when a small white shape scampered across a yard and jumped onto a stump:

Albino Squirrel 2020-03-03 - 680 crop
Albino Squirrel 2020-03-03 – 680 crop

If you’ve ever seen a gray squirrel, you’ll recognize the shape, even in this gritty enlargement:

Albino Squirrel 2020-03-03 - 680 - detail crop
Albino Squirrel 2020-03-03 – 680 – detail crop

Wikipedia says this one is likely a leucistic white squirrel, rather than a true albino squirrel. There is, of course, a website. tracking “white squirrel” sightings.

The relevant coordinates, for science:

41°41'39.9"N 73°52'56.6"W
41.694410, -73.882374

Can’t say if this one had black or pink eyes, but it was pure white!

Batmax NP-BX1 Batteries

Having recently lost one of the year-old DOT-01 batteries, a quartet of Batmax NP-BX1 batteries for the Sony HDR-AS30V helmet camera just arrived:

Batmax DOT-01 Wasabi NP-BX1 - 2020-04
Batmax DOT-01 Wasabi NP-BX1 – 2020-04

The orange curve is the last surviving (“least dead”) Wasabi battery from the 2017-08 batch and the dark green curve just above it is another DOT-01 from 2019-02. The problem is not so much their reduced capacity, but their grossly reduced voltage-under-load that triggers a premature camera shutdown.

The Batmax batteries measure better than the craptastic Wasabi batteries, worse than the STK batteries, and should survive the next year of riding. As before, I have zero belief that Amazon would send me a “genuine” Sony NP-BX1 battery, even at six times the nominal price, nor that it would perform six times better.

Batmax is one of many randomly named Amazon Marketplace sellers offering seemingly identical NP-BX1 batteries: Newmowa, Miady, Powerextra, Pickle Power, LP, Enegon, and so forth. Mysteriously, it’s always cheaper to get a handful of batteries and a charger, rather than just the batteries, so I now have a two-socket USB charger:

Batmax NP-BX1 - USB dual charger
Batmax NP-BX1 – USB dual charger

Despite the “5 V 2 A – 10 W” and “4.2 V 0.6 A – 5 W” label on the back, charging a pair of batteries after a ride started at 700 mA from a USB 3.0 port. The charger makes no claims about USB 3 compliance, so I’d expect it to top out around 1 A from a generously specified port.

Losing the Battery Bag

Because the cheap batteries I use in the Sony HDR-AS30V camera provide just slightly less runtime than our longest usual ride after a year of use, I carry a spare battery in a small red felt bag. The bag also holds a USB card reader helping to make the MicroSD card somewhat less lose-able on its trips betwixt bike & desk.

Here I am, swapping batteries in Adam’s Fairacre parking lot before starting the trip home:

Losing the Red Bag - setup - 2019-02-25
Losing the Red Bag – setup – 2019-02-25

You can see it coming, right?

Eight minutes later, we’re turning onto the Dutchess County Rail Trail:

Losing the Battery Bag - flight - 2019-02-25
Losing the Battery Bag – flight – 2019-02-25

And then it’s gone:

Losing the Battery Bag - gone - 2019-02-25
Losing the Battery Bag – gone – 2019-02-25

Mary drove past there on her way to a distant meeting, but the little red bag was not to be found anywhere. Maybe it’ll reappear on a fence post or taped to the bulletin board; I’ve tried to return things I’ve found that way.

I expect somebody got a nice present and, if naught else, it’s good to drop happiness into the world.

There’s another reader and a quartet of batteries on their way.

Diamond-Drag Styrene Engraving: Line Width

Engraving all the Tek Circuit Computer scales on a single sheet of styrene plastic with a diamond drag tool produced a test piece with plenty of lines and characters:

Diamond on styrene - engraving test - in action
Diamond on styrene – engraving test – in action

I covered one quarter with good old black Sharpie, a lacquer crayon, and well-aged black acrylic wall paint:

Diamond on styrene - engraving test - raw color fill
Diamond on styrene – engraving test – raw color fill

Applying a sanding block removed the rubble + scribbles and brought the surface down to the engraved patterns:

Diamond on styrene - engraving test - 225 250 300g 2400mm-min
Diamond on styrene – engraving test – 225 250 300g 2400mm-min

The lacquer crayon doesn’t seem to adhere well to styrene:

Diamond on styrene - 225 250 g 2400mm-min - lacquer crayon
Diamond on styrene – 225 250 g 2400mm-min – lacquer crayon

A closer look shows I probably sanded off too much of the surface, perhaps above some grit below the sheet, because those lines almost vanish:

Diamond on styrene - 225 250 g 2400mm-min - lacquer crayon
Diamond on styrene – 225 250 g 2400mm-min – lacquer crayon

The crayon may adhere better to deeper lines. These are obviously too shallow and the pigment seems to come off in chunks:

Diamond on styrene - 300g 2400mm-min - lacquer crayon
Diamond on styrene – 300g 2400mm-min – lacquer crayon

The acrylic trim paint filled its patterns, despite having turned into a gummy mass during decades on the shelf:

Diamond on styrene - 225g 2400mm-min - acrylic paint
Diamond on styrene – 225g 2400mm-min – acrylic paint

The Sharpie ink, being basically a thin liquid, completely filled its patterns and (apparently) soaked into the rough side walls. The lines seem to be 0.1 mm wide at 225 g downforce:

Diamond on styrene - 225g 2400mm-min - Sharpie
Diamond on styrene – 225g 2400mm-min – Sharpie

They’re less uniform at 250 g:

Diamond on styrene - 250g 2400mm-min - Sharpie
Diamond on styrene – 250g 2400mm-min – Sharpie

A 300 g downforce produces (somewhat) more uniform 0.15 mm wide lines and slightly distorted characters:

Diamond on styrene - 300g 2400mm-min - Sharpie
Diamond on styrene – 300g 2400mm-min – Sharpie

I have no way to measure the actual engraving depth. If the 60° diamond tool had a perfect point, which it definitely doesn’t, then a 0.15 mm wide trench would be 0.13 mm deep. I’ve obviously sanded off some of the surface, so those lines could be, at most, 0.1 mm deep.

All in all, the engraving came out better than I expected!

Dutchess Rail Trail: Beaver Lodge & Dam

A beaver family built their lodge next to the Dutchess Rail Trail:

Beaver Lodge - DCRT N of Golds Gym - 2020-02-23
Beaver Lodge – DCRT N of Golds Gym – 2020-02-23

It’s just to the right of the fence post, on the far side of the pond.

Dutchess County’s aerial survey in 2016 showed a dry-ish area west of the rail trail, with a culvert to the north:

Beaver Lodge - DCRT N of Golds Gym - 2016 CIR image
Beaver Lodge – DCRT N of Golds Gym – 2016 CIR image

We went back the next day and stopped at the culvert. Their dam spans the entire near side of the pond, upstream of the ditch (just above my hand) leading to the culvert:

Beaver Lodge and Dam - DCRT N of Golds Gym - 2020-02-25
Beaver Lodge and Dam – DCRT N of Golds Gym – 2020-02-25

The helmet camera pictures look west from the rail trail, with the lodge in the northernmost open area. The wide-angle camera lens exaggerates the distance, but the lodge is only about 35 feet from the fence.

A stand of birch trees near the lodge now looks like a combination buffet and construction yard. When beavers discover ferrocement, their structures will become much more obvious.

Go, beavers, go!

Tek Circuit Computer: Styrene Engraving Test

Engraving all three Tek Circuit Computer decks on a single sheet of styrene plastic with the diamond drag tool:

Diamond on styrene - engraving test - overview
Diamond on styrene – engraving test – overview

The three patterns overlap here & there, but the intent was to have plenty of engraved lines for further study:

Diamond on styrene - engraving test - in action
Diamond on styrene – engraving test – in action

The vivid blue glare comes from a flashlight at grazing incidence off to the left, with brutal color correction back to something sensible.

Engraving each deck at a different depth gave a range of downforce:

EZ='EngraveZ=-0.5mm'
Runit Bottom Engrave

EZ='EngraveZ=-1.0mm'
Runit Middle Engrave

EZ='EngraveZ=-2.0mm'
Runit Top Engrave

I fed all three of those G-Code files into bCNC, applied them to the same sheet with the same origin touchoff, and it worked fine.

The tool holder rate of 200 g + 50 g/mm produced downforces of 225, 250, and 300 g. In retrospect, the range wasn’t really broad enough, so Moah Force may be in order.

The diamond produced plenty of swarf:

Diamond on styrene - engraving test - swarf
Diamond on styrene – engraving test – swarf

Wiping the surface with a strip of masking tape clears away the loose rubble:

Diamond on styrene - engraving test - cleaned
Diamond on styrene – engraving test – cleaned

The innermost scale comes from the top deck, engraved at 300 g. The long shadows from the plastic pushed up along the tick marks seem to indicate the deepest trenches, although I don’t have any way to measure their depth.

I scribed and snapped the sheet into quarters so I can (mis)treat the engraved patterns in various ways:

Diamond on styrene - engraving test - raw color fill
Diamond on styrene – engraving test – raw color fill

What a mess!