Crazy Dave's dogs and the stone wall
Tuesday, September 10 2019
I walked into the office again this morning to a jargon-filled conversation between Morning Dave and Gloomy Jon on the subject of golf. Neither guy strikes me as the golfing sort, and several weeks ago I learned why: the golf they both do is not conventional golf but is instead disc golf. This involved trying to land a Frisbee into a basket, and the kind of people who play it are much more likely to drive Priuses and eat health food than the practitioners of the kind of golf played with clubs and balls on Trump-branded properties.
At some point after getting home, I went into the nearby forest to continue with the building of that completely unnecessary stone wall I've been working on. I suspect part of what keeps drawing me back to it is the experience of being outdoors in perfect weather, doing something sweat-inducing with my body, which, if it has the sense that evolution would give it, craves real exercise. As I worked, Crazy Dave's three shepherd-adjacent dogs came bounding up the hill at me, barking, snarling, and rearing up to put their paws on the wall so as to get a better look at me. I ignored their menace, cooing at them gently and trying to pet them, but they wouldn't get close enough. Eventually Crazy Dave (whom I never actually saw) called them off, and they continued their walk. Crazy Dave is a creature of habit, and I was working on my wall at his dog-walking time, not far from his dog-walking route.
This evening I finally figured out how to get PWM working on the Raspberry Pi, at least on GPIO pin #18. With just one GPIO pin to work with, I used it to control the rover's drive motor and then added buttons to the controller web page that, instead of turning on motors and leaving them on, turn them on and leave them running briefly. For the main drive buttons, I made three buttons, all of which advanced the rover for two seconds but at three different PWM-dictated power levels. This made the rover behave a bit more like the kind NASA might deploy on another planet, and this made it much more easily-controlled in an indoor environment. Gretchen, who had just cooked us a dinner of taco casserole, was a bit skeeved out to think I might deploy a sight-enabled robot that could follow her around while I was off at work. At around that time, I managed to launch the poor rover off the edge of the stairs into the basement. The fall broke the steering harness in two places, though I was able to fix it on one side by drilling a hole and adding a screw to replace a now-missing pivot and on the other by supergluing in a strap of copper sheet metal to replace the broken hoop that had gone around a pivot. The tiny Raspberry Pi camera had also been flung from its carrier board, and it was only while retrieving it that I realized how small it is (about the size of a squashed pea). Despite these small setbacks, I was pretty happy with the state my rover (and its control software) were now in. I considered it enough of a completed project to justify the consumption of alcohol.
There is still one thing about the rover I don't understand: periodically the H-bridge-controlled motors (particularly for the steering apparatus) will spontaneously turn on and run until the battery is exhausted or I hear the sound and unplug the power. I'm not sure what is causing that.
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