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Yesteryear

Saturday, July 7, 2012

June 7, 2012


           This package was just sickening enough to reach top billing for today. Gamer grub, so those addicted to WoW now only have to take pee breaks. Give an American a computer and does he search for answers? Nope, he plays games and wonders why the world thinks he is an idiot. Now, idiots have their own “performance snack”, that’s what it says. If you look close, it’s got vitamins and neurotransmitters, for those obsessed with reaching level 60 Silithus. What a disgusting lot these gamers are, but then again, what are zero-sum, talentless, B-average, boring nobodies supposed to do when they turn 30 and discover they have no friends? No fair asking my family, that’s cheating.
           The beach here is just not enough to attract me, I stay home instead. How to explain this? Well, part of it is I have no tradition of hanging out on the beach. What’s more, after years of work, I find that I am psychologically tired by end of the week. I feel pooped. I don’t like going to the beach alone, but then, going with somebody else is always a logistics hassle.

           I’ve got 10 of my tunes recorded. The results are not enough to make me happy. While I know a solo act is complicated, the audience probably never pauses to consider that a bass solo is magnitudes more difficult than strumming a guitar. (The down beat on a bass is exactly opposite and most modern hits are written for the guitar.)
           The BR-600’s major flaw is that it is designed for the guitarist singer. Those are the only two tracks you can create simultaneously, and it records both inputs on both tracks. To isolate them, you have to go back and do both tracks over. This tune, “Cocaine Blues” with all the drum stops, is practically impossible to record with this machine. But it can be done so I’m proceeding to distance myself from any copycats.

           Reflecting on Billy-Bill’s call last day, we have a typical situation on hand which amounts to covers versus originals. Do we play other people’s tunes or our own? The trouble begins when somebody wants to do both, Glenn. This amounts to, in actuality, the guitar player faking way too much. And this is why, since age 14, I want to hear the guitarist do the cover note-for-note before listening to any “improvements”. That way, when there is an extra chorus tacked on, I am certain he can play the same song and know for certain when he cannot. Got that, Jim?
           I find that rule (no comping on my stage until after I hear the cover played right) is enough to weed out all the wannabes. There is one guitarist I would trust to play it right, and that is Larry Gustafson. Unbelievably gifted, he wouldn’t remember me, the scared and broke 17 year old who hitchhiked to town. I see he is still active in music and doing some recording up in Canada. The pictures on his album covers, however, were probably taken back then, ahem.

ADDENDUM
           Robotics and the test bench. We are to the limit of what can be done with what we have. I’d like to continue with this fascinating study, but it will mean acquiring “stuff”. To build a circuit with 200 parts, you need the 200 parts. For instance, I require a dedicated Arduino to test PWM code, but an Arduino is far too expensive for such usage. Here’s a test for you: what is PWM? It is pulse width modulation, the technique used to vary the speed of direct current motors.
           Here’s the easiest description on the subject you’ll ever find, compliments of me, the guy who didn’t become a teacher. DC motors require a constant voltage within a narrow range, say for example 6 volts or 9 volts. You can’t vary that voltage or the motor will either burn out or won’t “kick in”. Instead, you “pulse” the voltage off and on really fast and the motor reacts quite faithfully. Read on for a complete mini-course that includes both theory and practical.

           In robotics, pulsing the voltage on and off, say 45% on (or 55% off, same thing), will cause the motor to turn at 45% full speed. I’ve tested this extensively and it is astonishingly accurate, provided you supply that “pulse” at a consistent frequency. You could use rheostats, but we had this little chat last year. The rheostat isn’t accurate enough and that’s why your electric train sits there and hums, then suddenly leaps to a start.
           Last and most complicated twist: If you want your robot to move ahead at 60% full speed, it is not enough to pulse the voltage at 60%. You’ll get the rheostat problem, especially at very low speeds. Enter the Arduino, which is capable of outputting a frequency of 16 million pulses per second. At such levels, you can also control acceleration, and that’s what I want. You want it, also. To move at 60%, you want your robot to smoothly move up to that speed, not jackrabbit.

           This is where I need the extra Arduino. Said acceleration must be smooth from 0% to 60% and the relationship isn’t always linear. The PWM is controlled by code and each code change has to be uploaded via USB cable. Attempting this while your microcontroller is attached to a robot is lively exercise. For all three of your arms. I’m already designing code that reads a sensor, so the robot will slow by itself when it detects an obstacle. See, we’re already ahead of the obstacle-avoidance gang.
           In conclusion, slowing the robot down is important also. Using PWM you can eliminate the need for a braking system, as the motor will drag to a stop. The one thing you don’t want is a skid or lock-up. Until further notice, a tipped over robot is a dead robot. The Arduino can also control motor direction, which is accomplished by reversing the polarity of the power supply. This has other advantages, which I wonder who among you will follow up.

           Wait, there’s more. In another amazing coincidence, this issue’s featured project in “Nuts & Volts” is virtually the same circuit I described, photographed, and published right here concerning the decade counters. They even included the cascading seven-segment LEDs that I ran out of and which they like to let us know they have in unlimited supply. Their device displays the 15 digit national debt. My 4 digits display, well, 4 digits. Actually 5, because I bypassed the zero level.
           What do you know, another coincidence. Of all the sensors out there, which one do you suppose has been chosen as best for first time robot builders? See photo, my sonar sensor on the left, the robot kit on the right. And it is mounted on the same type of step motor swivel head that “looks” side-to-side for a clear path as I described five months ago right here. It is even “parked” at the 45 degree angle thought would make it look like eyes. If I find discover this robot has specialty acceleration modules in the code, you know dern well what I’m going to think: Tesla is alive and picking my brain or reading this blog. I also described an on-board readout and a memory-based decision chip.
           Look out world when we acquire a lab. Because I do not believe in coincidences.