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freedom of books
Sunday, September 25 2011
The Arduino-based controller that governs my hydronic solar array is like a semiconductor cerebrum that sits atop a much more primitive relay-based reptilian brain. The Arduino replaced a far simpler analog system that did little more than compare the resistance of thermistors with reference values, and the original plan was for the relays to handle most of the logic. They are still crucial to the system; the only information that comes out of the Arduino is whether or not hot water or the slab should be heated by the sun. In other words, that interface with the reptilian relay brain is only two bits wide. To make this data channel more useful, I've also added a single bit of data that travels the other way, telling the Arduino whether or not the information it has sent to the relays has resulted in the running of the circulation pump. It can then use this information to handle various contingencies (and even to determine on its own that the season has changed).
I often have a window open to the live log from the solar controller on Woodchuck (my main computer). This tells me the temperatures at the various sensors, whether or not heat should be collected, and if it actually is. If heat should be collected but it isn't being collected, then there's a problem. Ideally there would be some alarm that would sound, but for now I just have to notice this state in the live log. And today I happened to noticed that hot water collection was supposed to be happening, but the pump was off. After some investigation, it turned out that the actuator on one of the electric valves had died. This would be an easy replacement; the actuator is easily unscrewed from the valve mechanism without any messy plumbing work.
But when I went to search for the actuator, the Grundfos Powerzone, online, I found nothing useful. There were a few PDFs describing it, but nobody had it for sale. Was I going to have to cut out this valve and replace it with something more widely available? After more searching, I eventually found an actuator that looked exactly like the Grundfos Powerzone, but it didn't have Grundfos written on it anywhere. It was the Sparco Powertrack, and Sparco is a subsidiary of Honeywell. It seems that the Sparco product line had been sold by Grundfos to Honeywell, though the evidence for this was entirely circumstantial. No matter, I ordered a Sparco Powertrack from Pex Supply. Back in 2005, I'd bought the original Grundfos valves on Ebay because they were only $25 each; the replacement actuator cost more than twice that much.
On Tuesday we'd be getting new hickory floors to replace the nasty carpet in our upstairs master bedroom and teevee room, but before any of that work can be done, we'll have to remove everything from those rooms. Gretchen has been moving little things, putting them mostly in the bathroom. But today I used a handtruck to move two chests of drawers, revealing rectangles of carpet that hadn't seen the light of day in nearly nine years. The collection of dust bunnies were impressive. Mind you, I even consider dust bunnies to be a valuable resource and I would never put them in a landfill. I like to add them to the garden or other patches of barren soil, where the hairs (it's almost entirely cat hair and spider webs) serve as nitrogenous mulch that help prevent erosion.
Now that I have an e-paper-based ereader, I'm interested in stocking it with books. But it's not like I actually want to pay for them. A week ago I didn't know anything about ereaders or the formats of digital books, but today I learned about the epub format. If you have a file in the epub format, you can read it on an ereader (well, you can read it on mine at least). There are plenty of old books in the public domain available for free download in this format, and the first of these I loaded onto my ereader was Thomas Hardy's Tess of the d'Urbervilles. While it's all well and good to be able to access such classics, the public domain has been starved of content since the rise of the Disney corporation. Fortunately, though, it should come as no surprise that there's a thriving book piracy exchange happening on Bittorrent, with plenty of modern titles available in the epub format. I downloaded a bunch of these this evening. Suck it, Mickey Mouse.
For linking purposes this article's URL is:
http://asecular.com/blog.php?110925 feedback
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