One year ago today: August 11, 2013, Lavabit, R.I.P.
Five years ago today: August 11, 2009, interesting warnings.
Ten years ago today: August 11, 2004, TX crop circles.
MORNING
No word from Miguelito, my regular mechanic. He did say he might be in New York until the 14th, but usually he would check in by now. This matters because he represents the slim chance of me seeing that city, or at least being able to travel this month. The deal is the same, I’ll help drive there, but I need a train ticket back. We know the pattern by now, a nice journey outbound, then the quickest dash home “before dark”. Plus, New York has one of the few travel alternatives acceptable to me: an Amtrak station.
Speaking of Nova, here is the latest 3D printer object. I’m pleased that larger objects seem to be printing successfully but not pleased that the minority who own the printers are not flooding the rest of us with useful information concerning same. I have suspicions why this is. Further, I remain unhappy about the lack of overall learning at the meetups, they are a little too free-form for anything meaningful to get shared. I am not as interested in building a store-bought kit as the rest of the gang. [Author’s note: I don’t know what the piece being printed is. I don’t think it is part of our project.]
Thus, I intend to propose that a small five to ten minute lecture and question period be solicited from the membership at the beginning of each meet-up. The topics will be initially decided in advance, because we know what will happen if we let just anyone start taking over. Next, a high school in Miami needs a robotics consultant, so I threw my hat in the ring. Me? A consultant? I would not have thought so either before I attended Nova and learned where I stood in comparison to the eggheads. I have read 2,200 pages of advanced robot textbooks. Me, 2200; Nova, 0.
You know why I don’t like the Internet yellow pages? Crap, that’s why. Paid ads that appear no matter what criteria you enter. Put in “city parks” and you’ll get pawnbrokers, check-cashing stores, and a plethora of businesses that went bankrupt five years ago.
And, say the inventors of hamburger making robot, “Our goal is not to make employees more efficient. It is designed to obviate them.” The bot makes 360 burgers per hour, one every ten seconds. The last career option for the nation’s dropouts will be gone by 2025.
Here’s an Onion training video for those whose heart attacks are not as loveable as mine.
REST OF DAY
Blog rules, here is the most important new item today. For years I've been reading about the flyback diode on electric motors. When a motor turns off, the surrounding magnetic field collapses, so you need a precaution the resulting electric spike does not flow backwards down your wires. 100% of "experts" mention this diode, yet every last one of us knows [damn well] when you see an electric motor, you do NOT see a big fat diode across the power studs.
Hmmm, one of the most established businesses in this area, American Breakers (electrical supply) is terminating their 30-year employees. Next, I received a series of inquiries from Tallahassee concerning that eye doctor who refused to renew my eyeglass prescription. I don’t know if anything happened to him, but yes, I turned the guy in because as far as I was concerned he was over-billing the system. He demanded I get another expensive exam ($210) because he refused to renew a prescriptions barely over a year old.
This was the contentious part. It turns out I was right, the prescription does belong to me, not the doctor. There are normal limits for all prescriptions that are not contact or internal, and they are all longer than two years, most are good for five years. But the doctor was also right, in that he does not have to renew it at his discretion. I say his discretion was disgraceful on this one. Withholding a prescription to coerce the patient is not ethical. Again, I don’t know what gives, but I re-told them the exact facts, which I happened to have on file here to a degree of accuracy they found amazing.
But I also discover that most eye clinics have a limit on how may insurance patients they will take on and the earliest appointment may be in October. It may be even worse trying to see a dentist. Obamacare, my eye. Or is that, my tooth?
Next, the scooter brake system. It is acting up, seems to be the calipers. That further inhibits and trips except the necessary. So I went to the bingo haul, tested my equipment, and headed home for another quiet evening. I guess it must seem strange to those who don’t read why anyone would want to spend any precious time reading, but go figure.
This is all spin, for as far as we know, no other generals even tried. So, put another way, every general that could ever be bothered to cross the Rhine seems to have made it okay. In reality, the river is too long to be defended. Old Georgie just found a quiet spot and walked across. Some hero.
But how about those propaganda pictures. Here’s a Sherman rolling past a “knocked out” panzer, probably a Mk IV, a pre-war design. Note how the perspective makes the Sherman seem larger. And what is that plate welded across the front? Anyway, I see no evidence the panzer was lost in battle. The white smoke is behind the tank and the escape hatches are open. It probably ran out of
I also looked a mite deeper into what C+ calls “libraries”. These are pitiful attempts to extend the terrible inadequacies of C+ computer code. The guy who invented dot notation and the underscore connector needs to have his nuts cut off, though I doubt anyone could find them. Let me just say that anyone so woefully ignorant as to the role of punctuation marks in the English language can certainly not be trusted to write anything as demanding as computer code. What? You say they do write code? Yes, I see what you mean, and we can tell by the way our computers NEVER crash.
ADDENDUM
I fell asleep in the armchair while reading specs on servo motors. Can’t get a much quieter evening at home if you wanted to. If I don't wise up, I’m going to wind up missing this place. Anyway, I priced out the robot hand. The cost for the electronics is going to be $260. This is far out of the price range anybody over there [at Nova] seems willing to shell out. That’s even if they had a clue which servos to buy. I finally read enough on these motors to know what gives. Here is a picture of a partially wooden robotic arm. That’s arm, not hand, Nova.
That whining noise is the motor geared down to around 75 rpm, which makes it surprisingly strong. These motors work from 4 to 7 volts and normally can turn only 180°. They have a feedback built into them that tells you when the motor has reached the correct position and as such they are the only electric motors which can do this. To use as a drive wheel, you void the warranty by modifying the motor to rotate 360°. In this mode, the motor is expected to burn out in 25 hours.
Of all electric motors, they are the only ones built to a size standard. Mind you there are several different sizes, but each has the same dimensions of others it its class. The prices begin at around $15, the most basic robot will require two. One for steering; one for driving. These motors cannot be run by just connecting them to a battery, they require a programmed series of pulses from a microchip, or for those who have been following along, they work on PWM (Pulse Width Modulation).
Other drive motors require special gearboxes to reduce the speed and these tend to cost $50 each. There are options but they involve tradeoffs, such as gear damage if you stall the smaller motors even once. Last important detail is the feedback mech mentioned above works with a potentiometer. Some sources instruct the user to remove this device to convert the motor to continuous rotation. It works, but you lost a major function of the motor—the ability to measure its own distance traveled. With a robot, that’s kind of important, like.
You now know ten times more than the combined robotics meetup at Nova.
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