December 26, 2023

Yesteryear
One year ago today: December 26, 2022, droolworthy.
Five years ago today: December 26, 2018, Duff goes dumpy.
Nine years ago today: December 26, 2014, I don’t date them.
Random years ago today: December 26, 2002, Barbados airport customs.

           Japan got their copycat lunar lander into orbit around the Moon this morning. It will test a new pinpoint landing system, where current probes could be a couple miles off. The landing is slated for Jan. 20, which would make Japan the fifth nation to join that club. With the shutting of MaxPC, the era of the computer magazine ends. I admit I’ve not bought one in maybe twenty years. Have you heard of Spotta, the bug detection service? Not me until this morning, but there’s an explanation.

           I filter out most on-line “subscription services” for the simple reason they don’t accept cash. I clicked on a Spotta ad that said it would describe how it works. Wrong, it described how the billing works. From Spotta’s misdirection and scare tactics, I infer the cost to be around $200 - $300 per month per room. Millennial marketing at its worst. For the third year running, the Washington Post and LA Times, two of the worst rags, report double-digit drops in readership.

           This may go down in history as the Xmas that I spent fixing a septic tank. Using my experience from here, I eliminated the toilet, the drain pipe, and the main septic tank as the problem. I did not know about the distribution box, but that’s where I encountered an obvious problem, a grass-choked outlet. More accurately, something blocking the pipe that allowed the grass to mat. Yes, I am being paid handsomely for this chore. This photo shows the trench.
           I got the shovel out and dug to the end of what I believe is the leech pipe on the neighbor’s septic. Everything checked out except that clogged drain, which I could not clear. I tried the auger, a hooked wire, and finally a metal rod five feet long. What ever is in there is anchored and slippery. The pipe ran perpendicular to what I thought, since the other neighbor’s yard seemed too close of this type of drain. Thinking it must have a bend, I dug it out looking for a cleanout plug. Nothing, but it now appears the entire pipe is only twelve feet long. If I’m right about that, let’s save $5,000 and just replace the entire pipe. Finders keepers, I found this pry bar in the pit.

           This entailed shoveling around a ton of dirt, part because I had piled some of it in the way. There appears to be no secondary tank. We held a trench-side conference and decided the economic solution is to dig out that leech pipe, possibly to replace it. Pat me on the back, ten years ago I was not supposed to ever be able to lift a shovel again. This tuckered me out, still, so we canceled Festus Tuesday and I’m going downtown. “We” construction workers like to have a cold beer after a hot day. Return tomorrow for another episode of the septic saga.

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           The work is tiring and I had intended to grab that beer but once I plunked down for a coffee, it was game over. Maybe two hundred shovelfuls and I’m all in. Still, that’s enough work to be proud of, while I’m weary, I’ve no aches, hooray! How tired did I get? I played bass sitting down, something I regard as a bellwether of age. This is how the “rose hip” cactus is going, it’s a slow bloomer. The other photo is what I call CactusV2, the one along the fence, now 20 or more feet tall.

           Yep, that “Seminole Wind” song is now an orchestral treat. The other choice, “Turn The Page” isn’t ready but I’ll fake it. Any tune that has even a single minor chord gets extra attention from me, part of which is because I don’t like the mistakes most other bassists make with them. It’s those minor thirds, where you get used to them early or not at all (if you ask me). By 9:00PM I’m still awake by virtue of the only truly renewable energy source, coffee.

           How about this one, “Climate change is an Al Gore-ism.” I was looking at vacuum tubes. The original computers used relays, making them noisy, and I notice the noise does not bother me as much as others. I can tune it out. Electronics makes me glad and sad. I find it fascinating on the theoretical level but regret I cannot follow the formulas or the workings much past the basics. That has not stopped me studying them for what is now my 14th year. Today the goal was to gain a better understanding of ADC. This is where real-world analog waves get converted into digital values the computer can use.
           As seems normal practice for engineers, all available material presumes you have a natural knack for what they mean, which is hardly the case if you are over 30 and looking at it for the first time. My conclusion is that while digital is either 1 or 0, the digital devices are “mechanical” and therefore capable of values in between. Are you ready for the poor man’s explanation?

           Okay, electronically, the 1 is the presence of a voltage (usually 5V) and the 0 is the absence of voltage (usually ground or 0V). However, all the voltages in between are possible, and the finer (or smaller) gradients result in more accurate readings. I was further confused by the fact there are two components to this. One, how rapidly you take the measurement, and two, how finely you calibrate your ruler. I believe the quality of these readings is called the resolution.

           Again, this info is only what I gather. The number of times per second the reading is taken is determined by the “speed” or frequency of your computer chip, faster is better. That’s measurement number one. Measurement two is the “height” of the reading. This is determined by the bit-length of your software. If it is 8-bit, your sensor can return a value between 0 and 255 (28). That is, if your sensor returns 2.5V, the digital value is converted to 128. I know, only some people find this intuitive, and that is how the instructions are usually written, dammit.
           Not every port on your microcontroller can provide this conversion. It requires an extra chip called a register capable of rendering these intermediate values. The Arduino Uno has 6 of these “analog inputs” designated A0 thru A5. These have a 10-bit resolution (210) meaning they can convert the return voltage to a digital value between 0 and 1023. To test your understanding of this, can you see the same sensor value of 2.5V mentioned above would now have a digital value of 512. The more bits, the finer increments you can measure. (If this seems flakey, it is, there are apparently huge problems and trade-offs on how this is implemented in real life.)

ADDENDUM
           Phased arrays, from y’day. I was barely right, it has to do with the wave fronts of multiple emitters but vastly more complicated than I managed. When you have multiple beams, the wave fronts overlap harmonically in a way one set directly between the two emitters is the strongest, and it is narrower. If you get enough emitters, they can form a single beam, the other circular expanding waves are still there, but very much weaker. I learned this is called beam forming, a surprisingly descriptive term for electronics people to call something, duh. (All this is above my capabilities, but not my understanding.)

           The antenna dish does not move much. Think many small antennas instead of one big. What’s happening is the emitter is changing the pulse timing. This has the effect of moving the beam. I can see this is an offshoot of radar but the real advance was coupling this with computers to produce and image rather than a radar blip. Ah, so that is how ultrasound works and no wonder it is expensive. At this point I ran out of understanding. The videos showed graphs and readings I could not follow. I got what I set out for, enough is enough.
           During this research, I watch a quick video on “exploders”. That’s the box with the handle that Wiley Coyote plunges to detonate the dynamite. I knew it was a dynamo but I did not know it produced 1500V. I learned the handle has a ratchet system that works only when pushed to spin the dynamo at high speed. When the plunger reaches the bottom, it makes a contact that surges the electricity.

           Once again I come up with an idea that, as far as I know, is not mentioned on the entire Internet. The rotation rubber band sensor. The only “rotation” sensor online is a board that reads a 2^10 position of a pot (potentiometer), and applies that to some other task. It’s existence shows there are people out there willing to pay $40 for a volume knob that only works with a $35 microcontroller. It does not sense any rotation, it reads the resistance of where you twirled the knob. For Spinal Tap fans.
           Moving to science to find a solution, is there some other physical aspect that can be measured to infer the tension, or the propellor speed? If I can discover some means for this, the mechanics of using it to control the prop becomes a second step instead of the final goal. Foolish was I to think otherwise. I found a webinar on tension control, but it was an hour long and I could not take that lisping millennial accent for than two minutes. I’m here to learn, not to test my patience. Don’t bother searching controlled spin rate, you’ll get a golf site. I can think of several ways to control the rate, but they all do so by sapping energy directly away from the elastic. This experiment tells me how little I know about the topic.
           I may build a small test rack to see what I’m up against. I can tell there are two “tensions”, the wound up bands, and the pull from the ends toward the middle (called the “spring”). I know nothing of how to measure this other than maybe devising a scale. Can I figure on using something free, like gravity, to control the rate? Winding two pencils with an elastic band reminds me of how capacitors discharge.

Last Laugh