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.

Category: Oddities

Who’d’a thunk it?

  • Gas Grill Igniter: Design Failure Therein

    The Judges at the Trinity College Home Firefighting Robot contest use butane grill igniters to light the candles in the arenas, but the gadgets seem to have terrible reliability problems: very often, they simply don’t work. I brought a few deaders back to the Basement Laboratory this April and finally got around to tearing them apart.

    It seems they don’t ignite because the trigger’s safety interlock mechanism shears the plastic gas hose against the fuel tank’s brass outlet tube:

    Grill igniter with sheared gas tube
    Grill igniter with sheared gas tube

    I tried putting a small brass tube around the (shortened and re-seated) hose, but it turns out the trigger interlock slides into that space and depends on the hose bending out of the way:

    Grill igniter with brass tubing
    Grill igniter with brass tubing

    So there’s no easy way to fix these things.

    It seems to me that a device using flammable gas should not abrade its gas hose, but what do I know?

  • OPB815 Optical Switch: Always Measure Your Components

    Given this ID printed on the side of an old OPB815 optical interrupter switch:

    OPB815 Optical Interrupter Switch - detail
    OPB815 Optical Interrupter Switch – detail

    And this pinout diagram from a randomly chosen datasheet for that part number:

    OPB815 Datasheet Pinout Diagram
    OPB815 Datasheet Pinout Diagram

    One might reasonably be led to believe that the white dot on the part marks the LED anode. That’s what I thought, too, but the innards are actually rotated 180° from the picture: the dot marks the transistor collector.

    Took me a while to figure that out; I eventually tore one apart and used my pocket camera to look for the blue-white glare of the IR emitter.

    After the dust settled, I rummaged around in the impacted shitpile holding my paper documents and found the original 1982 datasheet, with my very own scrawled notes:

    Original OPB815 Datasheet Pinout Diagram
    Original OPB815 Datasheet Pinout Diagram

    Back in the day, the dot on pin 1 marked the transistor collector…

    Memo to Self: No, scanning all that old paper wouldn’t help.

  • Architectural Forethought: Lack Thereof

    Plumbing trim plate vs tiled wall
    Plumbing trim plate vs tiled wall

    This from a restroom near the new high school auditorium, rebuilt at vast expense over the course of several years. You’d think for all the big bucks, somebody would remember that trim plates require a flat surface.

    It’s not like I’ve never forgotten a detail in any of my designs. In this case, though, several different people surely noticed this situation and none of them were sufficiently empowered to fix the problem.

    I’ve got a ten cent bet with myself that this will never get repaired. I’ll likely never know, though, as my Shop Assistant graduates this year.

  • Mysterious Warning Glyphs

    Found this on the hand-cranked reel that deployed an outdoor table umbrella in DC…

    Table Umbrella Cable Winch
    Table Umbrella Cable Winch

    I think you’re not supposed to:

    • Stand under something held by this cable
    • Use it for motive power (?)
    • Hang from it

    I think they’re violating the first warning, as the cable holds the umbrella open over your head. On the other paw, it’s not a monster dead weight, so maybe it’s OK.

    The food was pretty good.

  • Look Alive!

    You know how, in those old cartoons, whenever the vultures started landing in nearby trees, that was an indication of trouble ahead for the hero?

    Turkey Vulture in pine tree
    Turkey Vulture in pine tree

    The local Turkey Vulture flock has a roost a few miles away and they’re often seen circling in the thermals overhead.

    A few years ago I encountered one dismantling a squirrel flapjack on the road:

    Vulture dismantling squirrel
    Vulture dismantling squirrel

    It’s an ugly job, but somebody’s got to do it…

     

  • Target Unit Pricing Amusement

    I’m not sure whether all unit prices must be converted to “per 100 count” or not, but it really doesn’t work out well for CFL bulbs (clicky for more dots):

    CFL 2-bulb pack
    CFL 2-bulb pack

    That’s $549.50 per 100 bulbs, if you can’t make it out.

    On the shelf below, however, a single-bulb pack priced out to $979 per 100 count, so the 2-pack is definitely a better deal!

  • Winter Wonderland

    The NYS DOT recently spiffed up Raymond Avenue in Arlington, installing three small diameter rotary intersections and rows of street lights with lenses cunningly contrived to glare directly in your eyes. Why installing black, non-reflectorized bollards two feet away from the travel lane at each crosswalk seemed like a good idea escapes me, too.

    Anyhow, it seems one of those streetlights was a bit too close to the corner. The ruts across the top of the picture came from a truck that evidently clipped the pole and  neatly fractured the entire aluminum (?) base casting without bending anything else.

    Fractured street lamp post
    Fractured street lamp post

    Further south, this wall in Wappingers Falls shows why flat-roof building aren’t such a great idea in snow country:

    Ice flow across wall
    Ice flow across wall

    That isn’t a new problem, by the way. Last year it looked like this:

    Ice-covered gas meters
    Ice-covered gas meters

    Not much one can do: water goes where it will.