Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
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.
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.
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:
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…
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:
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.
It’s easier to remove the leadscrew while dismantling the carriage and apron, which requires removing the cover from the control box containing all the switches & knobs. Come to find out the “cover” actually holds all the gadgetry onto the headstock:
LMS mini-lathe – control box interior
I want to replace the Power indicator with something visible in normal shop light; judging from the connectors and overall brightness, it’s a neon bulb inside a green housing.
Anyhow, the four screws holding cover to the headstock weren’t identical:
LMS Mini-lathe – cover screws
I thought the oddball screw was deliberate, perhaps fastening that corner to a plastic frame of some sort, but it turned out to be a quick fix for a boogered tap job:
LMS Mini-lathe – mistapped cover hole
A bag of 4 mm knurled brass inserts will arrive in a while, after which I’ll drill out all four holes and epoxy inserts in their place. Might have to use stainless hardware, just for nice…
The Smell of Molten Projects in the Morning 