One year ago today: September 9, 2013, fifteen years today,
I've been seeking.
Five years ago today: September 8, 2009, the Nathanburger.
Ten years ago today: September 8, 2004, the last
Loch Ness picture?
MORNING
I spent the morning in a junkyard. First, breakfast at Senor's, but all about planning. We now have all the aluminum we want. But no way of bending, cutting, or rivetting it properly. And the popular 1/16th inch thickness, $5 a length at Home Depot, is not that easy to find second hand. Anyway, the eBike prototype is repaired, the one that, ahem, got run into a police car in broad daylight last month. In pieces longer than 4 inches, the metal is like working with any other. Smaller pieces must be returned here to be shaped on the benchtop.
While all this transpires, for the first time Agt. M and I discussed the topic of evolution. He does not "believe in it", nor that the Earth could be billions of years old. I took the opportunity to explain that the theories he was objecting to, such as plate tectonics and natural selection, did not actually say the things he had been told. For clarity, he had been taught that the theory of evolution said that man "descended" from apes--which it does not say.
For example, evolution does not state species evolved by natural selection and geology does not state the planet is 4.5 billion years old. They merely state that a lot of things which otherwise could be considered phenomena could be explained if one adopts or accepts those theories as a premise, as a starting point. But if you outright reject the theory, then you have little business discussing it's existence. It is not going away because there is too much real evidence.
The Grand Canyon is a prime example. If you accept that silt forms a layer on the bottom of the ocean a certain average thickness every year, when you count one million layers, well, there you go. That is not the same as proof the canyon is that old, it is merely one explanation. And that is why it is called a theory. The canyon could be described as catastrophic, suddenly appearing in final form in 4004 BC, or it could be the result of very simple forces acting over a much longer period of time. The only way to know the difference is to examine the evidence--unless something is preventing one from believing any evidence. Oh, those are just fossils, they say, where's the REAL evidence?
He [Agt. M] had never heard this definition of theories before, but still rejects the theories as "false". Of course, I don't confront religious objections, but they tend to get it backwards. A theory cannot be "proven" false unless it never works. That's quite different than saying a theory is false because it doesn't work in one particular case, or even in the majority of cases. Put another way, any theory that is right in even one case is a valid theory if the case can be duplicated.
Author's note 2015-09-08: here's another way to look at the man-ape controversy. People like Hector and Ken and I have a common ancestor. That is correct, if you go back far enough, all humans have a common ancestor. We are descended from that ancestor, but not from each other. Intelligence-wise, those guys and me are two different species. And no matter how long they evolve, they will never, never be as intelligent as a normal human being. But yes, we do have a common ancestor, but somewhere along the line, they diverged down the "dumb-as-shit" pathway. End of joke for the day.
NOON
I watched a couple of somewhat advanced videos on sonar. Like a lot of us, I thought a sonar echo was a cause and effect way to find a submarine. But to locate and position the object is not so easy when you involve navigations principles to deliver a weapon onto the sub. So, I chose the easy case where the sound beam goes straight down and bounces off the sea bottom. The biggest problem is knowing the speed of sound through various water densities and temperature.
I'll guess the easiest way is to use some mechanical method or find a known depth, then calibrate the sonar to read the same. Then I dropped in to the the barber shop to see if Abe recovered. Let me tell you what I told him. The guy is ten years younger than me and there is no way he should have gotten so tired on a day trip. I'm the one that had the heart attacks and I was walking circles around him.
I also growled him over not speaking up around women. Like I told my business partner forty years ago, if you do not even try, you relinquish the right to complain. Abe and I never chummed around before, but he was so shy it was like babysitting. I flat told him there is no such thing as trying too hard, if you ain't getting the women, you are not trying hard enough. Is that clear enough? The only men who try too hard are the ones who spend all their money on chasing women. Right, Ken?
But that brings up the trite phrase about women, "All the good ones are gone." There is always one total loser (and I do mean total) who will say that isn't true. A loser doesn't have anything to contribute, does not know the stats, and is insulting you by implying good women are everywhere and you can't cut it. And I've got $20 bucks that says the loser is paired off to some dweeby broad who hates him. Return tomorrow, and I will define what I mean by "good ones" and "all gone". Then you decide who has put the more thought into the situation.
EVENING
I've only ever heard of a single case of a pressure cooker exploding. And that as a documentary case of a unit with the safety valve clogged by boiling beans. This evening, I got a call from Guitar Eddie, up in the Carolinas. He managed it. Took out four of his ribs. He is now housebound on anti-biotics, proabably lucky he doesn't have pneumonia.
What's more, they don't make pressure cookers out of cast metal any more, so it is practically impossible to have an accident. There are three safety mechanisms and the rulebook says don't fill the bucket more than 1/3. Follow that instruction and there is never enough steam to cause an accident.
But we'll suppose Eddie had some ancient model. Even then, they don't really explode. They crack and the steam hisses out like an old boiler. And old boilers give plenty of warning when they are about to burst. So, come on Eddie, what's really cooking?
ADDENDUM
Totally concerned with robotics.
Distance measurement. We can't do it yet, but we don't even worry about competition these days. A useful 'bot has to move and know where it is. A week later, I can easily spoof the sonar sensors. These $30 gadgets have a small list of design flaws that keep them strictly beginner's level toys. We are far from done with them yet but the worst glitch is how they react to a moving object. As always, and somewhat differently than other club members, I might add, I "enact" all projects on paper before proceeding. Money has been saved by the barrel allowing me to sketch out the performance before we start building. Consider the following.
In this way, I had the algorithm worked out to have the robot navigate a maze of books stood on the floor, a maze of pretty much any complexity. The robot shown (in the above video) is the trivial case of avoiding the walls. But you see it miss openings mine would detect.
My design, using the same wheeled robot base (which I rejected as being an overly expensive kit) examined two methods of navigation. The one shown, in which the robot approaches to within a preset distance of an object, stops, scans for the longest uninterrupted path, and moves that direction. This involved placing the sonar on a swivel mount. Step angle on my unit was 30° compared to the 45° they used. But I didn't know what angle was appropriate.
While the demo robot moves continuously, mine would have moved ahead a few inches, stopped, and scanned again, side to side. This was because in those days, we had only one sensor. Now we have a box full of and side-mounted units would allow the 'bot to continually keep away from walls. Also, my robot presumed an on-board memory, where it could opt to use the strategy that worked before. In other words, my design was not store-bought. Hey, I like that, instead of calling it a robot, call in a store-bot. Let me work on that.
The demo 'bot uses infrared (IR) sensors to scan sideways. These type are not as dramatic looking, but they have taken over from the sonar as my study topic. They are come in more varieties, mainly used for camera focusing, and use real parallax to determine distance. In a way, we are looking for lack of distance, we want the robot to avoid anything it can pick up. Most challenging is having the robot find and enter through an open doorway.
The infrared "eye" is sensitive to reflected, but invisible, light. The idea is to place reflective tape on the sides of the door frame and aim a low-power laser at it. It is not enough to merely detect the image. As the robot approaches the door, the sides will appear to move further apart. But even that instance has the assumption the door is directly ahead of the beam.
So where are we at? Refer to last day's picture of a book. Page 645 contains this quip, "The distance betwen the tapes indicates the distance between the robot and the doorway. Should the robot be at an angle to the door, the tapes will not be parallel. Their angle, distance, and position can once again be interpolated to provide the robot's position relative to the door."
See, I never thought of that. Move to either side of the door and the sides will appear out of parallel.
And last for now, so you will know we are no slouches over here, the above findings do not rule out my robot pausing every few moments. Anyone who has worked in an office knows that having information and acting on it are two separate situations. I think most bot videos have edited out the problems, that they don't really work all that well. An obstacle-avoiding robot could technically move around without actually knowing were it is. And we, who have plumbed celestial navigation, can certainly do better than that.
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