101 uses for an old smartphone, 1
I'm about to install a freezer in the barn, which is half a mile from my home. How am I going to know if the power fails or the internal temperature rises?
Various companies sell ultra-low power temperature sensors which communicate via Bluetooth, for example the TI SensorTag (which actually does far more, but it's temperature I'm interested in just now)
It is said to run for a year on one button cell.
Editing and clojure revisited: this time, with structure!
Yesterday I blogged on editing Clojure, and commented that
"So after all that I'm going to talk about how wonderful it is to be able to do structure editing in Clojure, aren't I? No, sadly, I'm not, because (as yet) you can't."
Well, you can now. About tea-time yesterday, fooling around with Clojure, I worked out how the 'source' macro works — it retrieves the source of the function or macro whose name is its argument, by inspecting the metadata tagged to the symbol. So, you can retrieve function definitions. They're retrieved as strings from the file, but the read-string function parses s-expressions from strings, so that isn't a fatal problem. And having found that, a terminal based structure editor was not far away.
On editing, and Clojure
Back in the days when the world was young and we had proper software development tools, you'd write your top level function and evaluate it. And, of course, it would break, because you hadn't yet written your lower level functions. So you'd get a break inspector window pop up on the screen, and in that you could do one of several things.
Firstly and most obviously, you could supply a value as the return value of the function you hadn't yet written, and continue the computation. Secondly, you could inspect the stack, unwind a few levels of computation, and choose a different point to continue from, supplying a new return value there. But thirdly...
Thirdly, you could write your new lower level function right there on the stack, and continue the computation through your new function. And you could write it in a structure editor.
A staggered cantilever house
I'm back to worrying again at the structural design of a house to fit into the natural hollow in the north-east corner of my croft, a house to fit organically into the landscape. It isn't that I've fallen out of love with the Winter Palace, I haven't. I like it very much. So long as I remain single, and remain fit enough to climb its stairs, it suits me very well. But it is my ambition some day to cease to be single, and within the next twenty years the stairs will probably become beyond me. So in the long term another house is necessary. And the view from this house is very restricted; from the hollow in the north east corner I could see out to the Isle of Man.
So let's go over the options for that hollow. The first option I designed was the design I called Sousterrain: four tessellated concrete domes, supported by beautifully sculptural flying buttresses. The merits of that design remain that its irregular, sculptural shape would fit very well into the landscape, that it is iconic and would be beautiful; and, in so much as the design is modular, extending it would actually be easy. The demerit is that it uses a lot of concrete, a lot of embodied energy. An eco-house it is not. A further technical problem is that if the waterproofing of the back wall were to fail, it would be extremely expensive and difficult to fix.
So the next design was the design I called Singlespace: a mostly-timber conical roof over a single large, circular room, later (in the Longeaves variant) with some sheltered external storage and the possibility at a later stage of adding an earth closet attached to the building, which one could use without going out of doors. Again, the design is elegant. But for me the major demerit is that the regular cone, even if turf-roofed, would look significantly unnatural. It would draw the eye in the landscape, immediately announcing something artificial. Also, if the back wall were not to suffer the same waterproofing issues as with Sousterran, there would have to be a significant walkway round the back, which firstly wastes space and secondly interrupts the continuity of the walking surface between the natural hillside and the roof. There would be, in effect, a chasm to be stepped over, or fallen into.
A farewell to pigs
Tonight I have bagged up 12Kg of sausages, 9Kg of chops, 4Kg of spare ribs. I have salted one 7Kg ham, and I have another one waiting in the cool box. In refrigerators and freezers up in the void there is a veritable mountain of pork...
But I get ahead of myself. This week is the first time we've had pigs commercially slaughtered. Previously, we've slaughtered pigs here on the farm, but if you do that firstly need cool weather, and secondly you can't sell the meat, or even give it away. Two pigs, each of them substantially bigger than me, are far more than I can eat; and processing them would have needed me to call on a lot of support from friends.
So after a lot of swithering I decided to get them slaughtered commercially. I organised for them to go to Lockerbie slaughterhouse, and organised for them to be delivered from there to my favourite butcher, Henderson's in Castle Douglas. Again, if you slaughter commercially, you have to have them butchered in a commercial standard, health approved butchery, or you can't sell meat. Henderson's, apart from being my butcher of choice, also quoted a very favourable price — £50 per pig.