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.
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.
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:
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.
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.
The Smell of Molten Projects in the Morning 