Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
Those aren’t alarm pushbuttons. These are alarm pushbuttons:
Submarine Albacore – alarm pushbuttons
They’re in the USS Albacore and obviously intended for use by someone in a hurry: the tactile shapes tell your fingers everything they need to know. If I understand the ship’s history, the Collision Alarm switch contacts closed only during tests, although they did have a close call with the sub towing the (unpowered) Albacore from the Philly boneyard to its final resting site.
According to the information we saw, the control board was refitted / replaced / redone to remove classified hardware, so the woodgrain Formica background may not be original. On the other hand, this was a sub intended for extensive experimentation, so maybe they used a cheap and easily machined material.
We toured the USS Albacore (AGSS 569) in Portland NH and found this placard in the forward Escape Trunk (which doubled as the normal hatch during the sub’s nautical lifetime):
Escape Trunk Operating Procedure
One of my relatives is a submariner who seems calm & collected enough to remember that entire checklist in an emergency.
The camera lens they used for their virtual tour pictures would lead you to believe there was actually enough space inside the sub to inhale. That was not the case and I was very glad to have only half a dozen other people touring the sub with us.
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.
An old mill building built along a New Hampshire river had a pair of walls meeting at an acute angle:
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
That steel post certainly took a direct hit at some point in its career, though…
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…
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
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.
The Smell of Molten Projects in the Morning 