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sizing up tabbies
Friday, June 28 2013
Late this morning I went to my dentist in West Hurley to have my finished crown installed on the remnant stump of my "punk rock tooth." The old crown had been made of metal and hadn't fit very well, allowing food to work its way underneath is and fester. The new crown was made of semi-translucent porcelain and would hopefully fit much better. The dentist took pains to work filling in between the crown and the stump and then to grind the joint perfectly smooth. We'll see how it performs; my last crown didn't start going bad until it had been in my mouth about four years.
I had the dogs with me, so on the drive home I stopped at the West Hurley Park to give them a run. We ended up walking all the way to the north end of the utility road that the Town of Hurley uses to access stores of various materials that can be kept outside in piles: mulch, bluestone, iron rebar mesh, large components of sewer systems, pipes, and gravel. Recently the town had expanded its soccer field 50 feet or so northward by bulldozing into a patch of forest. It's not easy to coax athletic fields out of the rocky soil present at that site, and the process of smoothing out the terrain had produced an impressive pile of bluestone fragments. None of these were especially large, but there were many pieces that would serve as "bluestone glue" in the making of a proper bluestone wall, so I gathered about as much as I thought my existing rear tire pressure could handle.
Back at the house, Gretchen called from the Ulster County SPCA to ask if I wanted to come over and help select our next cat. Nigel's disappearance had opened up his slot, one that had previously been occupied by Wilma, Lulu, and Mavis. So I drove over and eventually joined Gretchen in the main cat room with its 30 or 40 cats and four or five volunteers (who, on this day, tended to be late middle-age white women). The idea was to adopt an older cat that was unlikely to get adopted by anyone else. Such a cat had to be good with dogs and other cats and not have odd dietary requirements. Candidates for us included a youngish middle-aged cat named Marie. She was a lanky wild-type tabby with a permanently non-plussed look on her face. I thought she was beautiful, but Gretchen seemed to think she might end up being another Julius (aka "Stripey"). Her preferred cat was an older orange-and-white tabby named Kira. She was plump and mostly just lay there the whole time (meanwhile Marie was jumping from one high perch to another and mostly avoiding our attempts to pet her). Gretchen was also interested in a one-eyed black cat, but he hadn't been at the shelter long enough for anyone to know how well he related to others. In the end we couldn't make up our minds. We ended our experience at the shelter by walking our two dogs (which I'd brought) in the fields adjacent to Suburban Propane. We tried to enter a forest full of ancient abandoned buildings (41.943951N, 74.017223W), but were driven out by clouds of mosquitoes.
Meanwhile back at the house, I continued struggling with the mysterious problem that was preventing my solar controller from activating the relays that open the necessary valves and turn on the circulator pump. By this morning I'd changed my theory and had become suspicious of one of those relays, but when I experimentally tried hooking up another identical relay in its place (without actually having to remove or disconnect the original), I found that the solar controller couldn't activate the replacement either. So I began suspecting the ULN2003s again. What I needed was a ULN2003 from a different batch to see if perhaps all the ULN2003 replacements I'd been trying were defective. I looked through my stores of integrated circuits and my piles of old circuit boards and couldn't find any ULN2003s. But then I happened to remember that I'd saved the last pre-LCD-display iteration of the Arduino-based solar controller in a box labeled "Old Solar Stuff." Not only did it still have its ULN2003 on its board, but the chip was socketed as well! I knew that it had worked reliably for years, so if it didn't work in the contemporary solar controller, I was overlooking something important.
As it happened, I missing something important. When I tested the solar controller with that old trusty ULN2003, it failed precisely as it has been failing with the suspect ULN2003s. What the hell? Was I going crazy? In desperation, I tested continuity between various pins on the ULN2003 and the terminals they should have been connecting to on the boiler room wall near the relay box. Sure enough, pin 9, the pin that should have been connected to ground, wasn't connected to anything. It seems a jumper that had been on the solar controller board, one that would allow me to connect pin 9 either to the local ground of the board or to a totally separate ground less likely to pollute the electronic environment, had fallen off. All I had to do was install a new jumper and the solar controller worked as before. But of course it was now working much better than before, because now it no longer had a tendency to reset itself in response to noise on the serial cable.
For linking purposes this article's URL is:
http://asecular.com/blog.php?130628 feedback
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