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: Home Ec

Things around the home & hearth

  • Monthly Science: Baking Powder Desiccant

    Being that type of guy, I tucked a bag of silica gel desiccant and a humidity indicator card into a #10 can of baking powder, then recorded the bag weight whenever I refilled the kitchen container:

    Baking Powder Can with Data
    Baking Powder Can with Data

    For reasons not relevant here, we pretty much stopped using baking powder a couple of years ago, so there’s a protracted silence between the last two data points:

    That last point emptied the can and, after a few days in the 60% RH basement, the bag weighed 243 g. The slope of the line suggests it’s been near 240 g for a while, although the humidity card showed the air was reasonably dry in there.

    At our current rate, we’ll open the next can in a year or so …

  • J5 Tactical Flashlight: Loose PCB

    I’ve been using the J5 Tactical flashlight as a “walking light” on our walks around the neighborhood, because its bright white spot has definitely caused a few drivers to look up from their phones at the last moment and swerve away.

    Of late, however, it turned on with a weak light and operated erratically. Removing the lens and unscrewing the front end revealed one mmmm potential problem:

    J5 Tactical Flashlight - loose LED PCB
    J5 Tactical Flashlight – loose LED PCB

    It looks like they’re depending on the “gold” in cutaway plated-through holes to make electrical contact with the aluminum mount, then through the threads to the case. The PCB joint would work much better with consistent pressure all the way around its perimeter.

    I mashed the PCB into place with a machinists vise, but, given the number of problems I’ve had with J5 flashlights (one a QC reject), they’re on my Non-Preferred Vendor list; if I’m going to get junk, I may as well pay bottom dollar.

  • 2015 Subaru Forester Battery

    With the intent of being able to find a picture of the battery in our 2015 Subaru Forester when I need it:

    The manual says the “battery type” is 55D23L, with a 48 A·h capacity.

    Here in the US, we measure a battery’s physical size with “Group Size” numbers which have no relation with JIS numbers, despite some overlapping or similar numeric values. The money quote:

    Definition of Group Size: The Battery Council International (BCI) assigns numbers and letters to common battery types. These numbers and letters are standards for maximum container size, location and type of terminal and special container features.

    So, it’s random. Choose a retailer, feed in the automobile year / make / model, and discover I need a Group 35 battery.

    The label includes “390 CCA”, which is the Cold Cranking Amps rating:

    The rating refers to the number of amps a 12-volt battery can deliver at 0°F for 30 seconds while maintaining a voltage of at least 7.2 volts

    So, if you’re building an automotive gadget and expect the battery to deliver something like 12 V, you’re wrong. Bonus protip: look up “load dump” to get an idea of the highest voltage.

    The “20 HR 48 Ah” specifies the Reserve Capacity:

    Amp Hour or C20 is an indicator of how much energy is stored in a battery. It is the energy a battery can deliver continuously for 20 hours at 80°F without falling below 10.5 volts.

    So a constant load of 2.4 A would do the trick, should you leave a few lights on overnight during the summer. In wintertime, you’re on your own.

    Because hell hath no fury like that of an unjustified assumption, the terminals are on the top surface toward the rear, with the positive lug on the left when you’re standing at the front bumper. That may be the “L” in “D23L”.

    Long ago, I ran afoul of an automotive battery which required knowing the terminal chirality and, of course, I bought the wrong one. Now I have a picture!

  • Encrypted Email: What Could Possibly Go Wrong?

    So this arrived from an email address similar to, yet not quite the same as, the URL of a physician’s office where I had an appointment a few days hence:

    Encrypted Email Message
    Encrypted Email Message

    My email client is set to prefer plain text, disallow remote content, and not open attachments, so that’s as far as it got. Donning asbestos work gloves and face mask, I pried open the message and its attached HTML file with the appropriate tools and found, as expected, scripts doing who-know-what.

    Called the office and, also as expected, was told my appointment time had been changed.

    Showed up, mentioned it to the doctor, and was told the office must check off many boxes to demonstrate its HIPAA compliance.

    Bottom line: HIPAA now requires patients (a.k.a., us) to open random attachments from random senders, all in the name of privacy.

    Banks do that, too.

  • Tea Strainer: Tare Weight

    Being a responsible consumer, I carefully measure my daily green tea dosage. A laser-cut stainless steel strainer and silicone steam cap recently arrived, with a most auspicious tare weight:

    Tea Strainer - 80.88 g
    Tea Strainer – 80.88 g

    Before my Genuine IBM 5160 PC XT with an 8088 CPU, I scratch-built a Z80 “personal computer” and wrote a primitive multitasking OS. Plenty of electrons have flowed through the transistors since those days.

    A great way to start the day; ya can’t make this stuff up!

  • Stink Bug Haven

    We hung a pine-cone wreath beside the back door (a.k.a. the only door we use), replacing a Welcome sign painted on a slate tile. Of course, the tile had long provided a sheltered spot against the house siding:

    Marmorated Stink Bugs and Spiders
    Marmorated Stink Bugs and Spiders

    Reports from the garden suggest Brown Marmorated Stink Bugs aren’t as damaging as they once were, perhaps because something has developed a taste for them.

    We hope whatever it might be eats well this year.

  • Cable Ports vs. Foot Traffic

    Spotted this under a counter at Panera Bread:

    Power and network cables - floor plates
    Power and network cables – floor plates

    You’re looking downward from the edge of the communal meal countertop at the power and network cable ports in the floor. The cables snake into the counter legs and emerge at the countertop to provide AC power, USB charging, and wired  network ports in addition to ubiquitous WiFi: all the conveniences of modern dining.

    Alas, down at floor level, the poor cables get kicked against the edge of their cover plates, bent with no strain relief, and seem jammed under the sharp edges of the leg extrusions. I expect the connectors below the hatches also endure a nightly bath of gritty water, with bonus salt during the winter months.

    And, yes, the AC power plug sits halfway out of its socket, with the blades exposed.