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: Oddities

Who’d’a thunk it?

The Curious Incident of the Dog in the Night-time

We are not dog people, so being awakened at 12:45 one morning by a large dog barking directly under the bedroom windows wasn’t expected. After a bit of flailing around, I discovered the dog parked under the windows on the other end of the bedroom:

Dog on patio

That’s entirely enough dog that I was unwilling to venture outside and attempt to affix it to, say, the patio railing, where it could await the town’s animal control officer in the morning:

Dog upright

It’s not a stray, because it wears two collars: one with leash D-rings and the other carrying a black electronics box that could be anything from a GPS tracker to a shock box that’s supposed to keep it inside one of those electronic fences. If the latter, a battery change seems past due.

Being a dog, it spent the next two hours in power-save mode on the patio, intermittently moaning / growling / barking at every state change in the back yard: scurrying rodents, falling leaves, far-distant sirens, neighborhood dogs, you name it. We would be dog people to want that level of launch-on-warning, but we’re not.

If parvovirus were available through Amazon Prime, I’d be on it like static cling. By the kilogram on Alibaba, perhaps?

Grainy photos taken in Nightshot IR mode with the DSC-F717, which works well enough after I (remember to) jiggle the Memory Stick to re-seat the ribbon cable connections.

Hat tip to Sherlock in Silver Blaze.

2016-08-21
Garden Shelter, Now With Toad

Mary used a garbage can lid to shelter some plants, left it in the garden for a while, and a critter moved into the new shelter. She first noticed two well-prepared front entrances:

Garden shelter – front entrances

And a rear entrance or, perhaps, the emergency exit:

Garden shelter – rear entrance

Gingerly lifting the lid, she found a dismantled bird corpse:

Garden shelter – bird corpse

Along with a large stash of sour cherries from a nearby bush:

Garden shelter – sour cherry stash

A good-size toad kept an eye on the proceedings:

Garden shelter – toad in lair

We didn’t know toads ate sour cherries, but the evidence seems clear:

Garden shelter – toad on sour cherries

The image of a toad taking down a bird can’t be unseen, but, more likely, a recently fledged nestling took shelter and couldn’t figure out how to get out again.

We’ll never know the rest of the story.

2016-08-13
eBay Listings: Read Carefullly

What’s wrong with this picture? (clicky for more dots)

eBay – 40 pin IDC cable – header

Not obvious?

Here’s the description, slightly reformatted for clarity:

New 5m IDC Standard 40 WAY 1.8” Multi-Color Flat Ribbon Cable Wire Connector

Description

Type: IDC standard.

10 colors, 4 group, total 40 pcs cables per lot

5 meter per lot.

width: 4.7 cm / 1.8 inch

Package content: 5M Flat Color Ribbon Cable

If you divide the 1.8 inch cable width by its 40 conductors, you find the wires lie on a 45 mil pitch. If you were expecting this “IDC standard” cable to fit in standard insulation displacement cable connectors with a 50 mil pitch, you’d be sorely disappointed. You can get metric ribbon cable with a 1 mm = 39 mil pitch, but this ain’t that, either.

Here’s what an individual eBay wire (black jacket) looks like, compared to a wire from a standard ribbon cable (red jacket):

Ribbon cable – 26 AWG – eBay vs standard

A closer look at the strands making up the wires:

Ribbon cable – 26 AWG – eBay vs standard – strands

As nearly as I can measure with my trusty caliper, the eBay ribbon cable has wire slightly smaller than 30 AWG, made up of seven 40 AWG strands, as opposed to standard 26 AWG wire made of seven 34 AWG strands. The good stuff might be 28 AWG / 7×36 AWG, but I was unwilling to break out the micrometer for more resolution.

I’d like to say I noticed that before buying the cable, but it came to light when I measured the total resistance of the whole cable: 80 Ω seemed rather high for 200 meters of 26 AWG wire. The wire tables say that’s about right for 31 AWG copper, though.

Changing the AWG number by three changes the conductor area by a factor of two, so you’re getting less than half the copper you expected. Bonus: it won’t fit any IDC connectors you have on the shelf, either.

Turns out a recent QEX article suggested building an LF loop antenna from a ribbon cable, so I was soldering all the conductors in series, rather than using connectors, and it should work reasonably well despite its higher DC resistance.

2016-08-11
New Coopers Hawk: Drying Time

Hawks lack waterproofing, which means devoting the morning after a torrential downpour to drying out:

New Coopers Hawk – drying

The dark bar across its back comes from an overhead utility line.

The male sparrow of the pair nesting in that box wasn’t pleased about the situation:

Coopers Hawk and Sparrow

Not much he could do about it, though …

2016-08-06
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
Staghorn Beetle Salvage Operation

This resembles nothing so much as a “developing country” shipbreaking operation:

Stag Beetle vs Ants – rear

For all I know, the ants haul the carcass into position, blow the scuttling charges to loosen the armor, and sink it in a convenient spot on the driveway:

Stag Beetle vs Ants – side

The hulk vanished later in the day.

This is the season for staghorn beetles; the one we spotted a few years ago was in much better condition.

2016-07-31
Fairchild and Stoddard RF Current Probes / EMC Field Sniffers

I’ve always wondered how noisy those Arduino + fake Neopixel lamps might be and these RF sniffers might come in handy:

Fairchild MFC-25 and Stoddart 91550-1 Current Probes

Even though they’re long obsolete, RF fields haven’t changed much in the intervening decades.

Fairchild Electronics may have become Electro-Metrics before they vanished in turn; the single useful search result offers a limited spec sheet that describes it as part of a set of three “loop probes covering the frequency range 10kHz-230MHz designed to search for RF magnetic leaks, especially in cabinets and shielded enclosures”. This one, with the blue coating, has a bandwidth of 22 MHz to 230 MHz. It has a TNC connector that now sports a cheap BNC adapter; note that it has standard polarity, not the reverse polarity required by FCC regulations that don’t take Amazon Prime into consideration.

Stoddard Aircraft Radio Co, Inc passed the 91550-1 baton to ETS-Lindgren, which (as of right now, anyway) offers a datasheet for a gadget that looks remarkably similar. The 30 Hz lower limit on the data plate suggests it’s roughly equivalent to ETS-L’s contemporary 20 Hz 91550-1L probe, but I doubt that makes much practical difference for my simple needs. The adapter takes the probe’s N connector to BNC.

The Word According to Mad Phil: If you can get to BNC, you can get to anything.

2016-07-28