Archive for October, 2016
Inside Another 9 V Battery
Posted by Ed in Electronics Workbench on 2016-10-31
A long time ago, I discovered some quasi-AAAA cells inside 9 V batteries:
Inside a batteries.com 9V battery
It occurred to me that I should dismantle a defunct Rayovac Maximum 9 V alkaline battery from the most recent batch (*) to see what it looked like:
Rayovac Maximum 9V battery – interior
Surprise!
A closer look at those pancake cells:
Rayovac Maximum 9V battery – detail
They look like separate cells bonded into a stack, although there’s no easy way to probe the inter-cell contacts; the leftmost cell probably died first.
(*) Which has apparently outlived the Rayovac Maximum brand, as they don’t appear on the Rayovac site.
Running Lights
Posted by Ed in Oddities, Recumbent Bicycling on 2016-10-30
New Cadillacs have thin white LED running lights along the front edges, with angular chromed trim below:
Cadillac running lights
Their SUVs have matching vertical-stripe taillight / markers; it’s obviously a stylin’ thing. If it weren’t for the power, I’d run LED strips along the edge of the fairing & seat frame on our ‘bents.
Probably due to having read Glory Road at an impressionable age, those lights always remind me of Heidelberg dueling scars:
Adolf Hoffmann-Heyden — Dueling scar
Cannot be unseen…
Good Signage Seems Difficult
As expected, the mis-assembled cart corrals in the Walmart parking lot remain that way. One corral has an additional feature that’s surely been there since Day 0:
Walmart cart corral – backwards and upside down
On the upside, that’s a high-reliability, high-availability trash can.
Vacuum Tube LEDs: 6H6GT Dual Diode
Posted by Ed in Machine Shop on 2016-10-28
Having accumulated a set of octal tube base clamps, it’s now a matter of selecting the proper clamp for each tube:
Octal tube base V-block clamps
The process of shell-drilling the tube base, drilling the hard drive platter, printing a tube socket and case, wiring up the Arduino and base LED, then assembling the whole thing requires a bit of manual labor, assisted by some moderately exotic shop machinery.
The getter flash atop this small 6H6GT dual diode tube rules out a cap and there’s not enough space for a side light:
6H6GT – on platter
Fortunately, the base LED completely lights the internal glass:
6H6GT – purple phase
The slowly changing color would make a fine night light:
6H6GT – cyan phase
It must be Art!
Cast Iron Pan Electrolysis: Anode Fragment
Posted by Ed in Electronics Workbench, Machine Shop, Oddities on 2016-10-27
Sacrificing a scrap EMI shield from a junked PC as the electrolysis anode, I grabbed a tab with the battery charger clamp:
Cast iron pan electrolysis – bucket
Turns out it didn’t survive the encounter:
Cast iron pan electrolysis – anode front
That white blob extends around to the other side:
Cast iron pan electrolysis – anode rear
Yeah, it got hot enough to melt a blob from the 6 gallon plastic bucket before burning through.
I tossed that into the garage so I wouldn’t forget it aaaand here we are …
Hand Sprayer Hose Kink Prevention
Posted by Ed in Home Ec, Machine Shop on 2016-10-26
Mary’s new half-gallon sprayer arrived with a kink in the hose just below the handle, which is about what you’d expect from a non-reinforced plastic tube jammed into the smallest possible box containing both the sprayer and its wand. Fortunately, the Box o’ Springs had one that just fit the hose and jammed firmly into the handle:
Sprayer hose with kink-resisting spring
The kink slowly worked its way out after being surrounded by the spring and shouldn’t come back.
That was easy…
Vacuum Tube LEDs: 5U4GB Vacuum Rectifier with Sidelight
Posted by Ed in Machine Shop on 2016-10-25
A larger version of the V-block clamp accommodates the 35 mm = 1-3/8 inch octal base of a 5U4GB Full-Wave Vacuum Rectifier tube:
5U4GB – spigot milling
The evacuation tip nearly touched the inside end of the base spigot!
I had to cut the shaft and half the body off the shell drill in order to fit it into the space above the tube base and below the chuck:
5U4GB – base shell drilling
A slightly larger shell drill would still fit within the pin circle, but the maximum possible hole diameter in the base really isn’t all that much larger:
5U4GB – base opening
The getter flash covers the entire top of this tube, so I conjured a side light for a rectangular knockoff Neopixel:
Vacuum Tube Lights – side light – solid model
There’s no orientation that doesn’t require support:
Vacuum Tube Lights – side light support – Slic3r preview
A little prying with a small screwdriver and some pulling with a needlenose pliers extracted those blobs. All the visible surfaces remained undamaged and I cleaned up the curved side with a big rat-tail file.
I wired the Arduino and Neopixels, masked a spot on the side of the tube (to improve both alignment and provide protection from slobbered epoxy), applied epoxy, and taped it in place until it cured:
5U4GB – sidelight epoxy curing
The end result looks great:
5U4GB Full-wave vacuum rectifier – side and base illumination
It currently sends Morse code through the base LED, but it’s much too stately for that.
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