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.

Author: Ed

  • Multimeter Banana Plugs

    The second banana plug on one of my multimeters failed, so I finally got around to replacing them with a dual plug from the Drawer o’ Banana Stuff:

    Dual banana plug - assembled
    Dual banana plug – assembled

    The bulky test leads don’t quite fit through the convenient retaining ring, so the zip tie holds ’em in place.

    A setscrew at the base of each banana jack tunnel crunches the test lead wire against the plug base, but, alone among the collection, this plug had one missing screw. Rather than toss it away (or, worse, back in the Drawer), I decided to Solve The Problem once and for ever:

    Dual banana plug - improvised clamp screw
    Dual banana plug – improvised clamp screw

    That’s an ordinary M3 screw from the Drawer o’ Random M3 Stuff with its head hacksawed off, a slot crudely hacksawed slightly off-center into the end, then lightly filed to hide the worst damage. With a bit of luck, nobody will ever notice it …

     

  • Knockoff RAMPS 1.4 Printer Controller Hardware Kit

    For 36 bucks delivered halfway around the planet, you can get a remarkable pile of gadgetry:

    RAMPS 1.4 - eBay parts
    RAMPS 1.4 – eBay parts

    With a bit of persuasion, it can become a 3D printer controller based on a RepRap RAMPS 1.4 shield or serve as a generic stepper / servo motor driver with three honkin’ MOSFET power switches, two thermistor inputs, a variety of I/O bits from the Arduino Mega PCB, and a monochrome LCD with a knob.

    The persuasion includes un-bending various header pins:

    RAMPS shield - bent pin
    RAMPS shield – bent pin

    Correcting bowlegged pin strips:

    And clipping offending pins:

    The interference between the bottom of the RAMPS power connector pin and the top of the Arduino Mega coaxial power jack seems baked right into the original PCB layout, which is puzzling. If you don’t trim the pins, this is as close as the boards will get:

    Well, of course, you could just jam all those headers together and bend the RAMPS PCB.

    The bent pin near the Reset button connects to the PS_ON output used to enable ATX-style power supplies. You connect the supply’s 5V_SBY always-on output to the VCC pin, which powers the Mega and most of the logic, but not the stepper motor outputs or the heaters.

    To make that work, remove D1 from the board where it’s snuggled along the header strip:

    RAMPS shield - D1 D2 locations
    RAMPS shield – D1 D2 locations

    D2, next to the fuse near the bottom of the picture, provides reverse-polarity protection for the RAMPS board.

    The servo motor power comes from the 5V pin. If you don’t need the PS_ON output and 5V_SBY input, then jumper the VCC and 5V pins together. Otherwise, you could solder-blob those pins on the bottom of the board, which means the servos are always powered.

    Configuring the latest 1.1.x version of Marlin should be straightforward …

  • Cocooning

    Each of the three Mystery Caterpillars wandered around the aquarium for a few minutes, found a spot surrounded by leaves, and tucked themselves into their cocoons.

    The smallest one went first and probably got the best site:

    Mystery Caterpillar - Cocoon 1
    Mystery Caterpillar – Cocoon 1

    The medium one:

    Mystery Caterpillar - Cocoon 2
    Mystery Caterpillar – Cocoon 2

    The largest caterpillar munched the leaf around the new cocoon and removed some of the silk (?) wrapper. It looks like the caterpillar’s fur falls off and becomes insulation inside the wrapper.

    The large one with mostly black fur managed to bind two leaves together:

    Mystery Caterpillar - Cocoon 3
    Mystery Caterpillar – Cocoon 3

    The Monarch remained calm, well above the scramble:

    Monarch Chrysalis - with skin
    Monarch Chrysalis – with skin

    The caterpillar’s skin (or whatever it is) remained loosely attached to the outside.

    All of which puts me in mind of Della Lu:

    FINAL WARNING!
    PROJECTION WILL SELF-ENCLOSE.
    CONTINUE?

    I wonder what they’re thinking after they type Y E S …

  • Praying Mantis

    It’s the season for large insects, but this Praying Mantis came as a surprise:

    Praying Mantis on screen
    Praying Mantis on screen

    Mary spotted it on the outside of the window screen in the front bathroom. We watched it for ten minutes as it strolled around the screen, all the while keeping at least one compound eye aimed at us.

    If humans were half as tall, those things would be terrifying!

  • Google Pixel vs. Clip-on Lenses

    The clip-on lenses for the (fancy) camera  in my soon-to-be-obsolete Google Pixel XL don’t fit well on the case I added to improve its griptivity:

    Pixel vs Lens Clamp vs Case - angle
    Pixel vs Lens Clamp vs Case – angle

    The upper half of the clip rests on the rim of the case around the bezel, with only the end of the foam pad against the glass:

    Pixel vs Lens Clamp vs Case - angle overview
    Pixel vs Lens Clamp vs Case – angle overview

    That’s pretty much the only stable position.

    Sticking a disk of stair-tread rubber on the foam adds just enough thickness to match the rim:

    Pixel vs Lens Clamp vs Case - aligned
    Pixel vs Lens Clamp vs Case – aligned

    The lenses came with two clips, so I left one unmodified to fit the Pixel without the case:

    Pixel vs Lens Clamp vs Case - clamps
    Pixel vs Lens Clamp vs Case – clamps

    Not that that happens very often, but …

    The lenses are about as good as you’d expect for ten bucks from Amazon. Stacking the 0.67 “wide angle” lens on the camera enlarges the field-of-view by a third with closer focusing at maximum zoom, so the minimum FOV drops from 2 inches down to 1 inch at a reasonable distance.  The 10x “macro” lens is basically useless, with a focus distance well within the Pixel’s shadow under any normal lighting; if I were that sort of guy, I’d conjure a small LED ring powered from the USB-C port.

     

  • Tour Easy Daytime Running Light: Now with Chirality!

    In the unlikely event our bikes need two running lights or, perhaps, a running light and a headlight, the solid model now builds mounts for the right side of the fairing, as before:

    Fairing Flashlight Mount - Right side - solid model
    Fairing Flashlight Mount – Right side – solid model

    And for the left side:

    Fairing Flashlight Mount - Left side - solid model
    Fairing Flashlight Mount – Left side – solid model

    Ahhh, chirality: love that word.

    Those pix come from a cleaned-up version of the OpenSCAD code that finally gets the 3-axis rotations right, after a rip-and-replace rewrite to deliver the ball model with its origin in the center of the ball where it belonged and rotate the ring about its geometric center. Then the rotations become trivially easy and a slight hack job spits out a completely assembled model:

    if (Component == "Complete") {
  translate([-BracketHoleOC,0,0])
    PlateBlank();
  mirror(TiltMirror) {
    translate([0,0,ClampOD/2]) {
      rotate([-Roll,ToeIn,Tilt])
        SlotBall();
      rotate([-Roll,ToeIn,Tilt])
        BallClamp();
    }
  }
}

    However, putting the center of rotation directly over the center of the base plate means the ToeIn rotation shifts the bottom of the clamp ring along the X axis, where it can obstruct the mounting holes. Shifting the ring by a little bit:

    ClampOD*sin(ToeIn/2)

    … keeps the ring more-or-less centered on the top of the plate. That’s not quite the correct geometry, but it’s close enough for the small angles needed here.

    Aiming the beam slightly higher makes a 400 lumen flashlight about as bright as any single LED in new car running lights:

    Fairing Flashlight Mount - Mary approaching
    Fairing Flashlight Mount – Mary approaching

    You can just barely make out the snazzy new blue plate on the left side of the fairing.

    A bike’s natural back-and-forth handlebar motion sweeps the beam across the lane, so I think there’s no real benefit from blinking.

    The OpenSCAD source code as a GitHub Gist:

    // Tour Easy Fairing Flashlight Mount
    // Ed Nisley KE4ZNU – July 2017
    // August 2017 –
    /* [Build Options] */
    FlashName = "AnkerLC40"; // [AnkerLC40,AnkerLC90,J5TactV2,InnovaX5]
    Component = "Complete"; // [Ball, BallClamp, Mount, Plates, Bracket, Complete]
    Layout = "Show"; // [Build, Show]
    Support = false;
    MountSupport = false;
    /* [Extrusion] */
    ThreadThick = 0.25; // [0.20, 0.25]
    ThreadWidth = 0.40; // [0.40]
    function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);
    Protrusion = 0.01; // [0.01, 0.1]
    HoleWindage = 0.2;
    /* [Fairing Mount] */
    Side = "Right"; // [Right,Left]
    ToeIn = 0; // inward from ahead
    Tilt = 15; // upward from forward (M=20 E=15)
    Roll = 0; // outward from top
    //- Screws *c
    /* [Hidden] */
    ID = 0;
    OD = 1;
    LENGTH = 2;
    /* [Screws and Inserts] */
    ClampInsert = [3.0,4.2,8.0];
    ClampScrew = [3.0,5.9,35.0]; // thread dia, head OD, screw length
    ClampScrewWasher = [3.0,6.75,0.5];
    ClampScrewNut = [3.0,6.1,4.0]; // nyloc nut
    /* [Hidden] */
    F_NAME = 0;
    F_GRIPOD = 1;
    F_GRIPLEN = 2;
    LightBodies = [
    ["AnkerLC90",26.6,48.0],
    ["AnkerLC40",26.6,55.0],
    ["J5TactV2",25.0,30.0],
    ["InnovaX5",22.0,55.0]
    ];
    //- Fairing Bracket
    // Magic numbers taken from the actual fairing mount
    /* [Hidden] */
    inch = 25.4;
    BracketHoleOD = 0.25 * inch; // 1/4-20 bolt holes
    BracketHoleOC = 1.0 * inch; // fairing hole spacing
    // usually 1 inch, but 15/16 on one fairing
    Bracket = [48.0,16.3,3.6 – 0.6]; // fairing bracket end plate overall size
    BracketHoleOffset = (3/8) * inch; // end to hole center
    BracketM = 3.0; // endcap arc height
    BracketR = (pow(BracketM,2) + pow(Bracket[1],2)/4) / (2*BracketM); // … radius
    //- Base plate dimensions
    Plate = [100.0,30.0,6*ThreadThick + Bracket[2]];
    PlateRad = Plate[1]/4;
    RoundEnds = true;
    echo(str("Base plate thick: ",Plate[2]));
    //- Select flashlight data from table
    echo(str("Flashlight: ",FlashName));
    FlashIndex = search([FlashName],LightBodies,1,0)[F_NAME];
    //- Set ball dimensions
    BallWall = 5.0; // max ball wall thickness
    echo(str("Ball wall: ",BallWall));
    BallOD = IntegerMultiple(LightBodies[FlashIndex][F_GRIPOD] + 2*BallWall,1.0);
    echo(str(" OD: ",BallOD));
    BallLength = IntegerMultiple(min(sqrt(pow(BallOD,2) – pow(LightBodies[FlashIndex][F_GRIPOD],2)) – 2*4*ThreadThick,
    LightBodies[FlashIndex][F_GRIPLEN]),1.0);
    echo(str(" length: ",BallLength));
    BallSides = 8*4;
    //- Set clamp ring dimensions
    ClampOD = 50;
    echo(str("Clamp OD: ",ClampOD));
    ClampLength = min(20.0,0.75*BallLength);
    echo(str(" length: ",ClampLength));
    ClampScrewOC = IntegerMultiple((ClampOD + BallOD)/2,1);
    echo(str(" screw OC: ",ClampScrewOC));
    TiltMirror = (Side == "Right") ? [0,0,0] : [0,1,0];
    //- Adjust hole diameter to make the size come out right
    module PolyCyl(Dia,Height,ForceSides=0) { // based on nophead's polyholes
    Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2);
    FixDia = Dia / cos(180/Sides);
    cylinder(r=(FixDia + HoleWindage)/2,h=Height,$fn=Sides);
    }
    //- Fairing Bracket
    // This part of the fairing mount supports the whole flashlight mount
    // Centered on screw hole
    module Bracket() {
    linear_extrude(height=Bracket[2],convexity=2)
    difference() {
    translate([(Bracket[0]/2 – BracketHoleOffset),0,0])
    offset(delta=ThreadWidth)
    intersection() {
    square([Bracket[0],Bracket[1]],center=true);
    union() {
    for (i=[-1,0,1]) // middle circle fills gap
    translate([i*(Bracket[0]/2 – BracketR),0])
    circle(r=BracketR);
    }
    }
    circle(d=BracketHoleOD/cos(180/8),$fn=8); // dead center at the origin
    }
    }
    //- General plate shape
    // Centered on the hole for the fairing bracket
    module PlateBlank() {
    difference() {
    translate([BracketHoleOC,0,0])
    intersection() {
    translate([0,0,Plate[2]/2]) // select upper half of spheres
    cube(Plate,center=true);
    hull()
    if (RoundEnds)
    for (i=[-1,1])
    translate([i*(Plate[0]/2 – PlateRad),0,0])
    resize([Plate[1]/2,Plate[1],2*Plate[2]])
    sphere(r=PlateRad); // nice round ends!
    else
    for (i=[-1,1], j=[-1,1])
    translate([i*(Plate[0]/2 – PlateRad),j*(Plate[1]/2 – PlateRad),0])
    resize([2*PlateRad,2*PlateRad,2*Plate[2]])
    sphere(r=PlateRad); // nice round corners!
    }
    translate([2*BracketHoleOC,0,-Protrusion]) // punch screw holes
    PolyCyl(BracketHoleOD,2*Plate[2],8);
    translate([0,0,-Protrusion])
    PolyCyl(BracketHoleOD,2*Plate[2],8);
    }
    }
    //- Inner plate
    module InnerPlate() {
    difference() {
    PlateBlank();
    translate([0,0,Plate[2] – Bracket[2] + Protrusion]) // punch fairing bracket
    Bracket();
    }
    }
    //- Slotted ball around flashlight
    // Print with brim to ensure adhesion!
    module SlotBall() {
    NumSlots = 8*2; // must be even, half cut from each end
    SlotWidth = 2*ThreadWidth;
    SlotBaseThick = 10*ThreadThick; // enough to hold finger ends together
    RibLength = (BallOD – LightBodies[FlashIndex][F_GRIPOD])/2;
    translate([0,0,(Layout == "Build") ? BallLength/2 : 0])
    rotate([0,(Layout == "Show") ? 90 : 0,0])
    difference() {
    intersection() {
    sphere(d=BallOD,$fn=2*BallSides); // basic ball
    cube([2*BallOD,2*BallOD,BallLength],center=true); // trim to length
    }
    translate([0,0,-LightBodies[FlashIndex][F_GRIPOD]])
    rotate(180/BallSides)
    PolyCyl(LightBodies[FlashIndex][F_GRIPOD],2*BallOD,BallSides); // remove flashlight body
    for (i=[0:NumSlots/2 – 1]) { // cut slots
    a=i*(2*360/NumSlots);
    SlotCutterLength = LightBodies[FlashIndex][F_GRIPOD];
    rotate(a)
    translate([SlotCutterLength/2,0,SlotBaseThick])
    cube([SlotCutterLength,SlotWidth,BallLength],center=true);
    rotate(a + 360/NumSlots)
    translate([SlotCutterLength/2,0,-SlotBaseThick])
    cube([SlotCutterLength,SlotWidth,BallLength],center=true);
    }
    }
    color("Yellow")
    if (Support && (Layout == "Build")) {
    for (i=[0:NumSlots-1]) {
    a = i*360/NumSlots;
    rotate(a + 180/NumSlots)
    translate([(LightBodies[FlashIndex][F_GRIPOD] + RibLength)/2 + ThreadWidth,0,BallLength/(2*4)])
    cube([RibLength,2*ThreadWidth,BallLength/4],center=true);
    }
    }
    }
    //- Clamp around flashlight ball
    module BallClamp(Section="All") {
    BossLength = ClampScrew[LENGTH] – 1*ClampScrewWasher[LENGTH];
    BossOD = ClampInsert[OD] + 2*(6*ThreadWidth);
    difference() {
    union() {
    intersection() {
    sphere(d=ClampOD,$fn=BallSides); // exterior ball clamp
    cube([ClampLength,2*ClampOD,2*ClampOD],center=true); // aiming allowance
    }
    hull()
    for (j=[-1,1])
    translate([0,j*ClampScrewOC/2,-BossLength/2])
    cylinder(d=BossOD,h=BossLength,$fn=6);
    }
    sphere(d=(BallOD + 1*ThreadThick),$fn=BallSides); // interior ball with minimal clearance
    for (j=[-1,1]) {
    translate([0,j*ClampScrewOC/2,-ClampOD]) // screw clearance
    PolyCyl(ClampScrew[ID],2*ClampOD,6);
    translate([0,j*ClampScrewOC/2, // insert clearance
    -(BossLength/2 – ClampInsert[LENGTH] – 3*ThreadThick)])
    rotate([0,180,0])
    PolyCyl(ClampInsert[OD],2*ClampOD,6);
    translate([0,j*ClampScrewOC/2, // insert transition
    -(BossLength/2 – ClampInsert[LENGTH] – 3*ThreadThick)])
    cylinder(d1=ClampInsert[OD]/cos(180/6),d2=ClampScrew[ID],h=6*ThreadThick,$fn=6);
    }
    if (Section == "Top")
    translate([0,0,-ClampOD/2])
    cube([2*ClampOD,2*ClampOD,ClampOD],center=true);
    else if (Section == "Bottom")
    translate([0,0,ClampOD/2])
    cube([2*ClampOD,2*ClampOD,ClampOD],center=true);
    }
    color("Yellow")
    if (Support) { // ad-hoc supports
    NumRibs = 6;
    RibLength = 0.5 * BallOD;
    RibWidth = 1.9*ThreadWidth;
    SupportOC = ClampLength / NumRibs;
    if (Section == "Top") // base plate for adhesion
    translate([0,0,ThreadThick])
    cube([ClampLength + 6*ThreadWidth,RibLength,2*ThreadThick],center=true);
    else if (Section == "Bottom")
    translate([0,0,-ThreadThick])
    cube([ClampLength + 6*ThreadWidth,RibLength,2*ThreadThick],center=true);
    render(convexity=2*NumRibs)
    intersection() {
    sphere(d=BallOD – 0*ThreadWidth); // cut at inner sphere OD
    cube([ClampLength + 2*ThreadWidth,RibLength,BallOD],center=true);
    if (Section == "Top") // select only desired section
    translate([0,0,ClampOD/2])
    cube([2*ClampOD,2*ClampOD,ClampOD],center=true);
    else if (Section == "Bottom")
    translate([0,0,-ClampOD/2])
    cube([2*ClampOD,2*ClampOD,ClampOD],center=true);
    union() { // ribs for E-Z build
    for (j=[-1,0,1])
    translate([0,j*SupportOC,0])
    cube([ClampLength,RibWidth,1.0*BallOD],center=true);
    for (i=[0:NumRibs]) // allow NumRibs + 1 to fill the far end
    translate([i*SupportOC – ClampLength/2,0,0])
    rotate([0,90,0])
    cylinder(d=BallOD – 2*ThreadThick,
    h=RibWidth,$fn=BallSides,center=true);
    }
    }
    }
    }
    //- Mount between fairing plate and flashlight ball
    // Build with support for bottom of clamp screws!
    module Mount() {
    TextRotate = (Side == "Right") ? 0 : 180;
    MountShift = [ClampOD*sin(ToeIn/2),
    0,
    ClampOD/2];
    difference() {
    translate([-BracketHoleOC,0,0]) // put bracket center at origin
    PlateBlank();
    mirror([0,1,0])
    translate([0,0,-Protrusion])
    linear_extrude(height=3*ThreadThick + Protrusion) {
    translate([BracketHoleOC + 15,0,0])
    text(text=">>>",size=5,spacing=1.20,font="Arial",halign="center",valign="center");
    translate([-BracketHoleOC,8,0]) rotate(TextRotate)
    text(text=str("Toe ",ToeIn),size=5,spacing=1.20,font="Arial",halign="center",valign="center");
    translate([-BracketHoleOC,-8,0]) rotate(TextRotate)
    text(text=str("Tilt ",Tilt),size=5,spacing=1.20,font="Arial",halign="center",valign="center");
    translate([BracketHoleOC,-8,0]) rotate(TextRotate)
    text(text=Side,size=5,spacing=1.20,font="Arial",halign="center",valign="center");
    translate([BracketHoleOC,8,0]) rotate(TextRotate)
    text(text=str("Roll ",Roll),size=5,spacing=1.20,font="Arial",halign="center",valign="center");
    translate([-(BracketHoleOC + 15),0,0])
    rotate(90)
    text(text="KE4ZNU",size=4,spacing=1.20,font="Arial",halign="center",valign="center");
    }
    }
    mirror(TiltMirror) {
    translate(MountShift)
    rotate([-Roll,ToeIn,Tilt])
    BallClamp("Bottom");
    color("Yellow")
    if (MountSupport) { // anchor outer corners at worst overhang
    RibWidth = 1.9*ThreadWidth;
    SupportOC = 0.1 * ClampLength;
    difference() {
    rotate([0,0,Tilt])
    translate([(ClampOD – BallOD)*sin(ToeIn/2),0,0])
    for (i=[-4.5,-2.5,0,2.0,4.5])
    translate([i*SupportOC – 0.0,0,(5 + Plate[2])/2])
    cube([RibWidth,0.7*ClampOD,(5 + Plate[2])],center=true);
    translate(MountShift)
    rotate([-Roll,ToeIn,Tilt])
    sphere(d=ClampOD – 2*ThreadWidth,$fn=BallSides);
    }
    }
    }
    }
    //- Build things
    if (Component == "Bracket")
    Bracket();
    if (Component == "Ball")
    SlotBall();
    if (Component == "BallClamp")
    if (Layout == "Show")
    BallClamp("All");
    else if (Layout == "Build")
    BallClamp("Top");
    if (Component == "Mount")
    Mount();
    if (Component == "Plates") {
    translate([0,0.7*Plate[1],0])
    InnerPlate();
    translate([0,-0.7*Plate[1],0])
    PlateBlank();
    }
    if (Component == "Complete") {
    translate([-BracketHoleOC,0,0])
    PlateBlank();
    mirror(TiltMirror) {
    translate([0,0,ClampOD/2]) {
    rotate([-Roll,ToeIn,Tilt])
    SlotBall();
    rotate([-Roll,ToeIn,Tilt])
    BallClamp();
    }
    }
    }
    view raw Fairing Flashlight Mount.scad hosted with ❤ by GitHub

  • Scrap Metal Prices

    Earlier this year, I finally hauled a pile o’ scrap metal to the recycler. For future reference, here’s what clattered down on the scale:

    Scrap Metal Prices - 2017-04
    Scrap Metal Prices – 2017-04

    I think the IRONY tag means ferrous bits & pieces in the mix. There’s a powerful motivation to hand them clean copper scrap, although I stop just after cutting off soldered pipe fittings and before stripping insulation.

    Memo to Self: Next time, ask about PCBs and gold-plated connectors.