Posts Tagged Improvements

Astable Multivibrator: RGB LED and Radome Spider

Well, a spider with half the proper leg count:

RGB LED - radome test

RGB LED – radome test

One could argue the LED spider has an unusually large abdomen, but I’m not going there.

The solid model looks the same way:

Astable Multivibrator Battery Holder - RGB LED Spider - radome

Astable Multivibrator Battery Holder – RGB LED Spider – radome

And, yes, those are eye protection caps over the four wire struts, most useful during construction while maneuvering the radome into position.

For reasons unknown to me, they’re called “Pirhana” LEDs:

RGB LED - wiring

RGB LED – wiring

I trimmed off half of each pin, soldered on 28 AWG color-coded silicone wires, threaded wires through openings, then rammed the LED package into the recess so it sits just below the radome’s curve. The dent matching the ball comes from the chord equation, as always, and looks pretty good.

The radome is, of course, a one-star ping pong ball from the usual big box retailer’s sporting goods section. The stamped logo sits at a random position with respect to the ball’s interior structure (visible when lit, as in the top picture), so I erased it with a fine-grit sanding sponge. Hollow plastic golf balls might work just as well, with an even more interesting surface texture.

The source code includes a cutaway look at the printed parts to verify their innards:

Astable Multivibrator Battery Holder - RGB LED Spider - fit view

Astable Multivibrator Battery Holder – RGB LED Spider – fit view

The OpenSCAD source code as a GitHub Gist:

The original doodles give useful dimensions, plus some details not withstanding the test of time:

RGB LED Radome Spider - doodles

RGB LED Radome Spider – doodles

The actual center-to-center distances for the wire posts come from the battery dimensions, rounded up or down as appropriate, to the nearest multiple of 5 mm, so those are just serving suggestions.




Shoe Lace Ferrules

A new pair of shoes arrived with extravagantly long laces requiring shortening. Years ago, I found heatshrink tubing completely unequal to the task, so I deployed Real Metal:

Shoelaces with crimped ferrules

Shoelaces with crimped ferrules

The ferrules come from a kit of such things, minus their plastic strain relief:

Ferrule terminals - hex crimper

Ferrule terminals – hex crimper

That’s a fancy hexagonal crimper for round-ish results. If you have a square terminal block, you should use the square crimper that comes with the kit.

Worked perfectly and produced immediate customer satisfaction.


Toy Cast Iron Stove Lid Lifter

This seemed appropriate for a day involving toys of all descriptions…

A cast iron stove (most likely a mid-last-century reproduction rather than a Genuine Antique™) emerged from a living room recess:

Toy stove with repaired lid lifter

Toy stove with repaired lid lifter

The line across the lid lifter handle shows where it broke, long ago, likely while being played with. Back then, I’d done a static-display-grade fix with a dab of clear epoxy, but a better repair seemed called for; my repair-fu has grown stronger.

I expected the handle to be pot metal, so drilling a hole in both ends for a music-wire stiffener seemed reasonable:

Toy lid lifter - laser alignment

Toy lid lifter – laser alignment

Much to my surprise, the carbide bit skittered off the surface, leaving fine swarf standing on the end. Turns out the lid lifter is cast iron, just like the rest of the stove!

Given that much of a clue, I aligned the pieces in a pair of machinist’s vises:

Toy lid lifter - alignment

Toy lid lifter – alignment

Slide apart (the vises stand on a smooth glass sheet; the nubbly side is down), dab silver solder flux on the ends, capture a snippet of 40% silver solder in the gap:

Toy lid lifter - silver solder setup

Toy lid lifter – silver solder setup

Hit it ever so gently with a propane torch and slide together:

Toy lid lifter - silver soldered

Toy lid lifter – silver soldered

The solder flows at 1200 °F = 650 °C, roughly corresponding to the blue-gray color near the joint. The nice purple (540 °C) on the left shows where I held the flame to start, with yellows (400 °C) on both sides. Good enough, sez I, it’s going to be a static-display exhibit.

Most of the solder went to the back side, so I filed it smooth and buffed off most of the heat coloration with a stainless-steel wire wheel in the Dremel:

Toy lid lifter - bottom

Toy lid lifter – bottom

A little more wire-brush action left the front side looking good:

Toy lid lifter - top

Toy lid lifter – top

As with most of the repairs around here, it simply makes me feel better …

Now, go play with your toys!

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Chair Reupholstering

We were tasked with replacing the foam cushion and seat covering on a pair of kitchen chairs. Removing the existing fabric seemed simple, until I pulled a dozen staples holding the cardboard cover to the bottom of the chair and exposed the fabric stapled to the MDF plate:

Chair reupholstering - stapled fabric

Chair reupholstering – stapled fabric

That’s just part of one corner. Obviously, whoever built the chair wanted to be very very very sure the fabric didn’t come loose!

Removing the staples from one corner produced a pile:

Chair reupholstering - one corner of staples

Chair reupholstering – one corner of staples

Piling up all the staples from the other chair looked even more impressive:

Chair reupholstering - staple pile

Chair reupholstering – staple pile

I fired maybe a third as many staples into the new fabric, which seems secure enough.



ShopVac vs. Samsung Vacuum Cleaner Bags

While cleaning the filter in the 1 gallon ShopVac for the bandsaw and lathe, I found the last few bags from the never-sufficiently-to-be-damned and long-gone Samsung vacuum cleaner that seemed about the right size for upcycling:

Shopvac vs Samsung vacuum cleaner bags - overview

Shopvac vs Samsung vacuum cleaner bags – overview

They’re a bit bulky:

Shopvac vs Samsung vacuum cleaner bags - trial fit

Shopvac vs Samsung vacuum cleaner bags – trial fit

It’s surely not worth buying bags just to cut ’em up, but, with a stock on the shelf, why not?


Motel Room Safe: Whoops

We spotted a pile of room safes in one of the motel stairwells:

Motel Room Safes in stairwell
Motel Room Safes in stairwell

Judging from what we found in the room, it’s out with the old and in with the new:

Motel Room Safes - mounting pedestal
Motel Room Safes – mounting pedestal

Too bad about the mounting pedestal, though: same size, different orientation.

Something unexpected always lurks in the datasheet


Monthly Image: Wall Painting

One day, long ago, this tree grew in a certain bedroom:

Outlet tree

Outlet tree

And then a flower appeared in the laundry room:

Outlet flower

Outlet flower

Much to our delight, she asked for forgiveness, not permission … which was, of course, granted immediately.