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like molten limestone
Sunday, May 17 2009
At some point there will be an Arduino-based microcontroller doing something in the greenhouse. That something will include taking temperature readings, but it might also include things like automatically closing insulated blinds at night or pumping well water up to a reservoir tank. To communicate with that controller from the comfort of the laboratory, I will be running some sort of serial cable, as well as a few other cables that might come in handy in the future: phone and ethernet. In addition to this, there will also have to be 120 volt electricity. Yesterday I laid out all the necessary cable (four runs of Cat 5e and one run of 12 gauge three-wire-plus-ground electrical cable) on the intended trajectory between the shop part of the garage part of the house (just beneath the laboratory) and the west wall of the greenhouse, approximately sixty feet away. And today I figured out a way to protect the electrical cable in its vulnerable spot as it emerges from the ground (all these cables will be buried). I have some old scrap three quarter inch copper pipe that is too old and sketchy for use as plumbing, but it would be perfect for use as conduit. I only needed a short (three foot) piece to protect the cable inside the fill that will eventually be piled against the west wall of the greenhouse. But as I was beginning to set up the conduit-covered electrical cable, I realized I still needed to do some more prep work to the quarter inch Wonderboard covering the styrofoam insulation on the outside of the the west wall. I needed to cover the top edge of the styrofoam, which was still naked and exposed to damaging ultraviolet light. So I mixed up some Portland cement, put down some fiberglass mesh, and spackled on the glurp. It's like working with molten limestone. (Though now I live in a land of sandstone and shale, it bears mentioning that I grew up in a part of the Shenandoah Valley where limestone is the only stone, and, despite that fact that it is more soluable in water than most rocks, I have always had great respect for it as a material.)
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http://asecular.com/blog.php?090517 feedback
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