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.

Month: August 2012

  • Panasonic CR123A Lithium Cell Capacity

    Picked up 25 Panasonic CR123A (more properly, CR17345) cells from the usual eBay supplier and put one to the test:

    Panasonic CR123A _ CR17345
    Panasonic CR123A _ CR17345

    Somewhat to my surprise, it delivers pretty nearly its full rated capacity at 400 mA discharge. It’d do even better at its 20 mA (!) rated current, of course, but I wasn’t up for a lengthy test…

    Yes, the nominal capacity spec is at 20 mA (C/77) discharge: one LED worth of current. Even the pulsed spec is only 900 mA at 10% over 30 seconds, which says a flashlight really puts the screws to the poor things…

  • SPD Bicycle Cleats: Wearout Thereof

    Mary decided her cycling shoes were worn out after about four years and maybe 8000 miles. Walking with cleated shoes doesn’t work well (no, we don’t bother with cleat covers), but they’ve seen a few miles of pavement, too:

    Worn SPD cleat in cycling shoe
    Worn SPD cleat in cycling shoe

    A closeup shows that the surface of the old cleat really has worn away:

    SPD cleats - new and worn
    SPD cleats – new and worn

    The rear tang is mostly there:

    SPD cleats - rear tang
    SPD cleats – rear tang

    But the front tang is mostly gone:

    SPD cleats - front tang
    SPD cleats – front tang

    New shoes, new cleats, new pedals… we’re still tuning for best fit.

  • Wouxun HT GPS+Voice Case: Colors!

    Rather than print another green case, the new, improved case has orange end caps:

    HT-GPS Case - End caps on build plate
    HT-GPS Case – End caps on build plate

    And a blue shell that’s a bit easier on the eye:

    HT-GPS Case - Shell on build platform
    HT-GPS Case – Shell on build platform

    Put ’em together and it certainly looks peppy, doesn’t it?

    HT-GPS Case - trial fit
    HT-GPS Case – trial fit

    That’s a trial fit with nothing inside, of course.

    Next step: circuitry!

  • USB Wire Color Code: Nobody Will Ever Notice

    A USB cable carries the analog mic and earbud audio for our bike helmets; the connectors are cheap, durable, and separate easily. I cut a 2 m “USB extender” cable (which, according to the USB guidelines, isn’t supposed to exist) near the A male connector, then wire that part to the helmet and the A female part to the GPS+voice board.

    The latest USB extender cable included a surprise:

    USB cable with yellow wire
    USB cable with yellow wire

    According to Wikipedia, there’s a standard color code for the wiring inside USB cables and yellow isn’t in the list. For this manufacturer, it seems that yellow is the new red.

    In previous USB extenders the red / black wires were a slightly larger gauge than the green / white data pair, but in this cable they’re not. That might matter if one expected the cable to carry, oh, let’s say an amp of battery charging current.

  • Storing Sherline CNC Mill Leadscrews

    After replacing the Y axis leadscrew, I decided that the X axis leadscrew was in fine shape, because it’s tucked under the table and not exposed to the swarf and grit that fell on the Y axis screw before I installed the bellows. Being that sort of bear, I couldn’t throw out the worn Y axis leadscrew, so I had two rather delicate rods that really needed more protection than a twist of paper.

    So I sawed off a length of 1 inch PVC pipe, faced the ends in the lathe, and added two rubbery endcaps from the heap:

    Sherline leadscrews stored in PVC pipe
    Sherline leadscrews stored in PVC pipe

    That fits neatly into the big box alongside the rotary table, with the bag of assorted nuts so they’re all together.

    Despite what you see there, the screws are wrapped in paper with a bit of oil, so it’s all good.

  • CO2 Capsule Fins: Party Edition

    CO2 capsules with multicolored fins
    CO2 capsules with multicolored fins

    These emerged from some recent printing sessions, where they served to join two successive colors as I changed ABS filaments.

    Whenever I give a talk, these are the last tchotchkes to go. Maybe some festive party fins will help?

  • Primo Comet Aneurysm: Teardown

    So, as you might expect, I couldn’t let the aneurysm on that tire get away without a closer look: had to haul the poor thing out of the trash and dissect it. Here’s what it looked like on the bike:

    Primo Comet Aneurysm - inflated
    Primo Comet Aneurysm – inflated

    The outer rubber has disintegrated and is pulling away from the Kevlar belt underneath, but it’s still holding air!

    Cutting that section out of the tire and flattening it makes things look almost normal:

    Primo Comet Aneurysm - flattened
    Primo Comet Aneurysm – flattened

    Peeling the rubber off the carcass reveals that the body cords have either broken or ripped loose under the belt:

    Primo Comet Aneurysm - peeled
    Primo Comet Aneurysm – peeled

    There was no external damage over that part of the tire and I was wrong about a gash in the Kevlar belt. However, the ends of the belt overlap just above and to the right of my thumb, so perhaps there’s a manufacturing flaw in there somewhere.

    Now it’s in the trash!