Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
While I was turning this year’s leaves into mulch for next year’s vegetables, a supervisor landed on my glove:
Pale Green Assassin Bug – front
I thought it was a very small stick insect covered with leaf chaff, but it turned out to be a Pale Green Assassin Bug nymph with built-in armor and spines:
Pale Green Assassin Bug – rear
Something like that, anyway.
This katydid supervised while I put the tools away:
Short-winged Meadow Katydid
Those scary stern claspers must come in handy for something, but I’d rather not be on the receiving end.
Just to see what happens, I tried cutting a shape from a scrap CD-R:
Laser cut CD – in progress
Cutting polycarbonate is a terrible idea, because that cloud consists primarily of The Big Stink™. AFAICT, the cutting fumes are not much more toxic than what burns off acrylic / wood / whatever, but they definitely smell much worse.
In any event, the laser produces a clean cut:
Laser cut CD – on platform
Modulo the charred edges and discoloration:
Laser cut CD – finished
Some of that buffs right out, but overall it’s not worth the effort unless you really need tiny diffraction gratings.
Until a month or two ago, when it began disconnecting randomly.
The camera cable has a standard USB A connector on one end and what looks like a 1.5 mm JST ZH connector on the other:
Laser cutter camera cable
Of course, it’s not quite long enough, so it plugs into a good-quality 1 meter USB 3.0 extender to the PC sitting atop the laser cabinet.
Some low-effort tweaks were unavailing:
Different USB ports
Different USB extension cable to the ports
Hub vs. direct
Eventually, some rummaging in the Box o’ USB Cables produced a cable from a different camera and, as you might expect, swapping the two identical cables solved the problem.
I have no idea what’s going on, but I’d lay significant money that when this cable gets flaky, swapping the original cable back in will solve the problem once again.
For reasons that will become relevant later on, I must clear the magazines from about ten feet of shelf space (and a stack of boxes), including this assortment:
To the best of my knowledge and belief, each collection is complete within those dates, although I’m equally sure an issue or two went walkabout over the course of four decades.
Having written columns for Digital Machinist, DDJ, and Circuit Cellar, I (still!) have multiple “author’s copies” of those, although I haven’t dug through the boxes for the specifics.
Here’s the deal:
You must take all of any set
Any offer ≥ $0.00 is acceptable
Shipping from ZIP 12603 is your problem
N.B.: Shipping Is Not My Problem (*)
Best offer on or before 30 November 2023 takes any or all.
Whatever remains becomes mulch in December 2023.
(*) A USPS Medium Flat Rate box (11×8.5×5.5 inch) costs $17 within the continental US and holds two or three dozen issues. Obviously, that’s the wrong way to ship an entire shelf of magazines, but gives you an idea of the scale.
If you want to pick ’em up in person, I’ll help heave ’em into your trunk.
It was a cool morning and the snake hadn’t yet reached operating temperature, but it eventually flowed off into the garage and we went on our way.
A few hours later we returned:
Garter snake under garage door seal – B
Apparently that was the best place for a snake.
Mary lined up a four-cell seedling pot ahead of the critter, encouraged it to flow forward, and much to our surprise it tucked neatly into one of the cells:
Garter snake under garage door seal – C
We carried it to the herb garden, wished it well, and a few hours later it had uncoiled and gone about its business.
While pondering what to do with the shattered kitchen scale, I got a bottom-dollar replacement touting its rechargeable lithium battery. After giving it the obligatory charge-before-using, I put it in service. Five days later, its battery was dead flat discharged.
So I gutted it to extract the battery:
Cheap digital scale – lithium cell
It’s a cute little thing, isn’t it?
Much to my surprise, the obligatory battery rundown test showed it matches its 0.74 W·hr label:
Kitchen Scale – Charge1
We all know where this is going, right?
Crunche a connector on the battery, another on the scale, and make up a suitable current tap for a meter:
Cheap digital scale – current measurement setup
Which looked like this:
Cheap digital scale – active current
That’s about what I found for the craptastic scale running from a pair of CR2032 primary cells, so it’s not out of line.
Turn off the scale and measure the idle current:
Cheap digital scale – inactive current
Do you think I got a dud?
For all I know, the little microcontroller under the epoxy blob is running a continuous attack on my WiFi network, with the intent of siphoning off all my sensitive bits. Ya never know.
Dividing the battery’s 200 mA·hr rating by 4 mA says it really should be dead in 50 hours, which is close enough to five days: diagnosis confirmed!
Rather than fight, I switched to a battery with more capacity:
Cheap digital scale – NP-BX1 replacement
It’s long past its prime, but ought to last for a month, which is about as long as the shattered scale survived on a similar battery.
The Smell of Molten Projects in the Morning 