Weatherproof Outlet Cover Re-Chaining
Posted by Ed in Home Ec, Machine Shop on 2019-07-08
The yard camera now resides outdoors and plugs into one of three outlets on the patio, all of which have weatherproof covers attached by a bead chain to the trim plate:
That’s the after-repair condition, as two of the three chains were broken when we bought the house.
Stipulated: the covers needed scrubbing, but sometimes ya gotta stay focused on the Main Goal.
Two feet of 3.4 mm brass bead chain (because spares: ya gotta have stuff) arrived from eBay, I dismounted all three covers, and discovered the bell-shaped brass caps on the old chains were perfectly serviceable after six decades:
The outlets are wired to circuit breaker 28, of course.
Having enough chain to go around, each cover now sports a slightly longer leash than before:
Reinstall in reverse order, the camera rebooted as it should, and it’s all good out there:
That was easy …
Arlington Fire Department Practice Session
Posted by Ed in Oddities, Recumbent Bicycling on 2019-07-07
The normal Vassar Farm exit was blocked by Arlington Fire District equipment, but the scene was calm and nobody objected when I asked to ride through:
They were practicing hose deployment and structure entry in a soon-to-be-demolished building:
That’s theatrical smoke, not a real fire; the folks off the right of the picture told me it’s impossible to burn down old structures for practice nowadays, what with all the environmental regulations.
The Tower Truck obviously has more reach than they’ll need for the second floor:
A few days later, we spotted Fairview Fire District folks scoping out the house.
We think this might be Vassar’s way of contributing back to the various emergency departments, as the College is mostly tax-exempt.
Runtime Error!
Spotted high on the wall of the local USPS office:
A closer look:
Huh.
The USPS uses VLC. Who knew?
I darken their doorway so infrequently I have no idea what’s normally displayed up there. Surely it shows advertisements for USPS products, which begs the question: why VLC?
Wrapping GCMC Text Around Arcs
Posted by Ed in Machine Shop, Software on 2019-07-05
GCMC includes a typeset function converting a more-or-less ASCII string into the coordinate points (a “vectorlist” containing a “path”) defining its character strokes and pen motions. The coordinates are relative to an origin at the lower-left corner of the line, with the font’s capital-X height set to 1.0, so you apply a scale function to make them whatever size you want and hand them to the engrave library routine, which squirts the corresponding G-Code into the output file.
Such G-Code can annotate plots:
Given that the plots appear on relentlessly circular CDs and hard drive platters, It Would Be Nice to wrap text around a circular arc, thusly:
The scaled coordinates cover a distance L along a straight line, so putting them on an arc will cover the same distance. The arc is part of a circle with radius R and a circumference 2πR, so … polar coordinates to the rescue!
The total text length L corresponds to the total angle A along the arc:
A = 360° L / 2πR
It’s entirely possible to have a text line longer than the entire circumference of the circle, whereupon the right end overlaps the left. Smaller characters fit better on smaller circles:
The X coordinate of each point in the path (always positive from the X origin) in the path gives its angle (positive counterclockwise) from 0°:
a = 360° x / 2πR (say "eks")
You can add a constant angle of either sign to slew the whole text arc around the center point.
The letter baseline Y=0 sits at radius R, so the Y coordinate of each point (positive above and negative below the Y=0 baseline) gives its radius r:
r = R - y
That puts the bottom of the text outward, so it reads properly when you’re facing the center point.
Homework: Tweak the signs so it reads properly when you’re standing inside the circle reading outward.
Converting from polar back to XY:
x = r × cos(a) (say "times") y = r × sin(a)
You can add an XY offset to the result, thereby plunking the point wherever you want.
This obviously works best for small characters relative to the arc radius, as the lines connecting the points remain resolutely straight. That’s probably what you wanted anyway, but letters like, say, “m” definitely manspread.
Overall, it looks pretty good:
A doodle helped lay out the geometry:
The GCMC source code as a GitHub Gist:
Security Theater: Combination Lock Division
When dialing the proper combination becomes too troublesome:
At a quick glance, though, it looks secure!
Security theater isn’t harmless, not that we have any say in the matter.
Whirlpool Refrigerator Drawer Support Re-Re-Re-Gluing
Posted by Ed in Home Ec, Machine Shop on 2019-07-03
Spring cleaning provided the opportunity for Yet Another Episode in my long-standing battle with the Whirlpool refrigerator entropy generator:
That little thing supports half the weight of the two drawers across the bottom of the refrigerator; how such a thin plastic member was supposed to be adequate to the task continues to escape me.
If we had to pay real money for all the repairs I’ve made to that piece of crap, we’d have replaced it long ago. The only thing that hasn’t failed so far is the compressor, so driving it until it drops continues to make sense; replacing a working anything seems like a bad idea.
KEDSUM LED Shop Lights: Cheapnification Thereof
Posted by Ed in Electronics Workbench, Machine Shop on 2019-07-02
As the basement’s fluorescent fixtures and lamps gradually die, I’ve been rewiring the fixtures for LED tubes, all bought from KEDSUM through Amazon. The first few batches looked like this:
The most recent two batches seem cheapnified:
The tubes show similar changes, going from a stylin’ version to a simple cylindrical cap:
The most recent carton label might lead you to think they’re counterfeits, but it could just be a simple typo:
There’s absolutely no way to tell what you’re going to get from any vendor on Amazon (or anywhere else, for that matter), so there’s no point in returning them, but I’d hoped buying “the same thing” from “the same seller” would produce a consistent result.
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