The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Day: November 4, 2016

  • Vacuum Tube LEDs: Mogul Base for 500 W Incandescent Bulb

    This obviously wasn’t ready for prime time, but it demonstrated feasibility with a socket on a base assembled for something else:

    500 W Incandescent - backlit light
    500 W Incandescent – backlit light

    I recently salvaged a heavy aluminum lid that looked like a perfect complement for that bulb:

    Mogul base - bulb - blue phase
    Mogul base – bulb – blue phase

    The light comes from a rectangular knockoff Neopixel in a sidelight mount:

    Mogul base - sidelight curing
    Mogul base – sidelight curing

    That’s epoxied to the rear of the bulb, below the equator, where it casts the best-looking shadow of the filament and support structures on the inside of the bulb. Actually, it’s taped in place for a week’s worth of burn-in to see if it survives.

    The Arduino Nano fits inside a small base below the ceramic Mogul socket:

    Mogul base - Arduino Nano holder
    Mogul base – Arduino Nano holder

    The braid exits through a hexagonal trench recessed into the top surface, with a dollop of epoxy holding it in place:

    Vacuum Tube Lights - Mogul Base - top - solid model
    Vacuum Tube Lights – Mogul Base – top – solid model

    The underside has holes for three 10-32 brass inserts:

    Vacuum Tube Lights - Mogul Base - bottom - solid model
    Vacuum Tube Lights – Mogul Base – bottom – solid model

    The center insert is the only thing holding the entire assembly to that aluminum base; I’m not convinced that’s enough, but it’ll suffice for now.

    The “computer” certainly gets lost under the ceramic:

    Mogul base - ceramic socket connector
    Mogul base – ceramic socket connector

    The base is slightly smaller than the ceramic to match the flat part of the lower surface; if it came all the way to the OD, you’d see an unsightly notch.

    The two screw heads buried down in the recesses thread into the outer brass inserts in the printed base. The ceramic Mogul socket mounts atop that connection block, with another pair of screws making both electrical and mechanical connections to the metal plates-with-screws that used to terminate the incoming power wires.

    It’s running the same Morse code firmware as before, with the Morse output turned off, because who needs a giant blinking bulb?

    The OpenSCAD source code of the base as a GitHub Gist:

    //———————-
    // Base for Mogul ceramic socket
    module MogulBase() {
    Insert = [5.0,7.0,10.5]; // 10-32 brass insert, used for socket and chassis mounting
    PCB =
    [45,18,7.5] // Arduino Nano
    ;
    BaseOD = 57.0;
    BaseOAH = Insert[LENGTH] + 3*ThreadThick + PCB[2];
    ScrewOC = 1.5 * inch;
    difference() {
    cylinder(d=BaseOD,h=BaseOAH,$fn=16*4); // overall shape
    translate([0,0,-Protrusion]) // central mounting insert
    PolyCyl(Insert[OD],Insert[LENGTH] + Protrusion,6);
    for (a=[90,-90]) // socket studs
    rotate(a)
    translate([ScrewOC/2,0,-Protrusion]) {
    PolyCyl(Insert[OD],Insert[LENGTH] + Protrusion,6);
    PolyCyl(Insert[ID],2*BaseOAH,6);
    }
    translate([(BaseOD – PCB[0])/2,0,BaseOAH – PCB[2]/2 + Protrusion/2])
    cube(PCB + [0,0,Protrusion],center=true); // Arduino PCB
    rotate(45)
    translate([0,0,BaseOAH – Ferrule[ID]/2 + Protrusion/2])
    rotate([0,90,0]) rotate(180/6)
    PolyCyl(Ferrule[ID],BaseOD,6);
    }
    }

    The original doodles with some dimensions:

    Mogul base - dimension doodles
    Mogul base – dimension doodles