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?

  • The Value of Childhood Rhymes

    Saw this in Lowell MA outside the Bootts Cotton Mill Apartments:

    DO NOT ENTER - unusual date
    DO NOT ENTER – unusual date

    The way I learned it:

    Thirty days hath September,
    April, June, and November.
    All the rest have thirty-one,
    Except February, which is all messed up.

    Maybe the River Walk reopens on the Twelfth of Never?

  • Sprinkler System Plumbing

    This Christmas Tree tops the fire sprinkler system in the Wentworth by the Sea hotel in New Castle NH:

    Fire sprinkler system plumbing
    Fire sprinkler system plumbing

    The long pipe leading around the corner to the left-front riser drains the test valve. The honkin’ big supply pipe stands to the rear of the regulators and valves. You can’t quite see it from here, but those water pressure gauges showed about 180 psi.

    The bathroom fixtures had the usual pressure and instant hot water, so there’s complex plumbing inside the walls, too.

    Some equipment, you hope just never get used…

  • Unusual Brick Corner

    An old mill building built along a New Hampshire river had a pair of walls meeting at an acute angle:

    Acute-angle brick corner
    Acute-angle brick corner

    Architects know that bricks, being the prototypical rectangular solid, generally don’t work well in such situations, but I suppose sometimes you just do what must be done and call it decorative:

    Acute-angle brick corner - detail
    Acute-angle brick corner – detail

    That steel post certainly took a direct hit at some point in its career, though…

  • Beware the Lurking Lorem Ipsum

    Fusion Hotspot Scrach-off Card
    Fusion Hotspot Scrach-off Card

    One of the motels we stayed at had a new (to me, at least) approach to the ubiquitous Free WiFi offering, which involved a small card with scratch-off fields:

    Being the curious sort, I checked their website to see what they were up to. The main heading, across the top of the page, read:

    Bringing wireless Internet capabilities to your property

    Visus, in vut eu in auctor mus sit odio ac habitasse non! Vut et ac ultricies urna, mauris enim magna mus ac urna arcu, etiam vel,

    Huh.

    The rest of the page has Lorem ipsum filler under every heading, including:

    24/7 Support

    Tincidunt ultricies magnis adipiscing. Natoque, augue mattis pid placerat mattis pellentesque adipiscing dis, habitasse scelerisque aliquet, ultricies lundium, lectus cras mus, sit? Magna turpis duis placerat massa in integer porta, sit, phasellus, nec, elementum, scelerisque in?
    Read More

    Clicking that attractive Read More link produces pretty much what you’d expect by now:

    Error 404 – Page not found!

    The page you trying to reach does not exist, or has been moved. Please use the menus or the search box to find what you are looking for.

    All the other links behaved the same way, including the Support header.

    Oddly, the Contact Us item hidden in the About us pulldown produced a form, so I sent off a message. Haven’t gotten anything back yet and really don’t expect to, either.

    It does give one pause to consider what happens to the bitstream between one’s tablet and the website. I make it a practice to not sign in to vital accounts while traveling…

    At least they didn’t use the Samuel L. Jackson slipsum generator

  • Wouxun PTT Voltage Limit

    TinyTrak3+ D6 - SMD Schottky diode
    TinyTrak3+ D6 – SMD Schottky diode

    It seems that Wouxun KG-UV3D HTs require nearly 0 V to activate the PTT input, which I discovered after the radio on Mary’s bike began acting intermittently. The TinyTrak3+ would transmit correctly, but the PTT button on the handlebar began to not work at all / work intermittently / work perfectly. The switch and cable were OK, pushing the button produced nearly 0 Ω at the 3.5 mm plug, the connections seemed solid, but the radio didn’t transmit reliably.

    I finally got the thing to fail on the bench, which led to the discovery that:

    • Shorting the PTT input to the GPS+voice adapter PCB to ground didn’t make the radio transmit and
    • Data bursts from the TinyTrack3 worked perfectly

    Gotcha!

    TT3 PTT In-Out
    TT3 PTT In-Out

    The TT3+ pulls its PTT OUT pin down from +5 V using a 2N2222A NPN transistor (off to the right in the schematic snippet), but, for reasons having to do with ESD, the input from the PTT switch on the handlebars goes through a 100 Ω series resistor, then passes to the TT3 board through PTT IN to D6 before joining the TT3 transistor collector. The low-active diode-ORed signal heads off through PTT OUT to a 10 Ω series resistor, thence to the KG-UV3D PTT input. D6 is an ordinary 1N4148, with the net result that the PTT input voltage at the radio dropped to 630 mV with the PTT button pressed.

    Not finding anything else wrong, I replaced D6 with a BAT54 Schottky diode that pulled the PTT voltage down to 300 mV and the radio worked fine.

    Of course, a BAT54 is a surface-mount diode, so I clipped off the unused no-connect lead (it’s the only way to be sure it doesn’t do anything) and tacked it down slaunchwise between the PCB thru-hole pads. If I had a BAT54C with common cathodes, I could replace both D5 and D6 in one shot, but D5 just pulls down a PIC input that has an ordinary logic-level threshold voltage.

    I don’t know why the KG-UV3D PTT is so fussy, although it may really be a current-driven signal that requires more current than can flow through the 110 Ω + diode forward drop in series with the PTT button. Wouxun presents no specifications that I can find.

    The identical circuitry on my bike works fine with the stock D6 diode and a presumably identical KG-UV3D. I should replace that diode before it gives me any trouble, but I’ll wait until I must take the box apart for some other reason.

  • Faucet Washers

    The slop sink in the rental house developed a drip and, unlike our kitchen faucet, required only a new washer. Of course, choosing the right size from that assortment posed a bit of a problem:

    Slop sink valve with washers
    Slop sink valve with washers

    The old washer is in the upper right; you can see the indentation from the valve seat.

    There’s a variety of sizes & shapes; these represent just the closest matches. I have no idea what 3/8, 3/8R, and 3/8L might signify, but they’re all slightly different, some with conical cross-sections that may also be slightly different. Worst case, of course, you can sand down the rim of a too-large washer to make the diameter come out right.

    [Update: a table of sizes mentioned in the comments.]

    The washer just in front of the old one has information molded right into the back: GOLDEN STATE 10¢ 1/2. Now there’s a show of confidence in price stability that you don’t see much any more!

    I found one that fit snugly in the recess of the valve stem, turned the screw tight, and it’s all good.

  • Glass Wine Corks

    The Locust Grove / Morse Estate (yes, that Morse) holds Sunset Sensations fundraisers throughout the year, wherein local restaurants and caterers prepare three food samples based on what’s growing in the historically accurate gardens and a local wine store selects matching wines. Mary and I volunteer as servers and they generally assign me to the wine table; being one of the few volunteers with Y chromosomes, I’m good at toting boxes and yanking corks.

    The most recent event featured Cusumano Insolia wine in bottles with glass stoppers:

    Glass wine corks - natural light
    Glass wine corks – natural light

    Front lighting with the flash makes them even more glittery:

    Glass wine corks - flash
    Glass wine corks – flash

    I’m thinking one of these atop a little box with an internal LED would make a dandy nightlight. Maybe etch the stem surface to add a bit of diffuse illumination?

    Perhaps I don’t get out nearly enough…