Author: mikal

This author has written 1354 articles

Beer fridge controller 0.2

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Further to yesterday's post about the beer fridge thermostat replacement, I've been hacking on ethernet support for the controller. This is handy because I'd like to log the temperature and compressor state over the network, because I'm hoping that can be used to make calculations about the thermal mass of the contents of the fridge, and therefore derive how much beer is actually in the fridge at any given time. Because the controller also supports more than one temperature probe, I'll also add more 1-Wire temperature sensors around the house so I can determine important things like if its hot in the outside world. The code is currently experiencing some bloat in the binary size, mainly because the ethernet library and the sprintf implementation are quite large. I'll have to think more about that. Here's the current code: #include <enc28j60.h> #include <etherShield.h> #include <ip_arp_udp_tcp.h> #include <ip_config.h> #include <net.h> #include <websrv_help_functions.h> #include <OneWire.h> #include <DallasTemperature.h> // Temperature sensor and compressor setup #define COMPRESSOR 9 #define ONEWIRE 3 #define HIGHTEMP 4 #define LOWTEMP 3.6 // 220L Kelvinator is 85 watts #define COMPRESSOR_WATTAGE 85.0 #define SLEEP_SEC 10 OneWire oneWire(ONEWIRE); DallasTemperature sensors(&oneWire); unsigned long runtime = 0, chilltime = 0, last_checked = 0, this_check…

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Beer fridge controller 0.1

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On the weekend I picked up a 220 liter beer fridge for $20. Its in really good condition (ignoring some minor rust in the freezer section), and the only real problem with it is that the thermostat doesn't work leaving the compressor on the whole time. Doug suggested that instead of just buying a new thermostat, we should build an arduino fridge controller. I'm not really a hardware guy, but once Doug had pointed me at the Dallas 1820 1-Wire temperature sensor, and lent me some resistors, it was pretty easy to pull the software side together. Note that this version doesn't actually do any of the compressor control -- it simulates that by turning a LED on. The compressor stuff has been delegated to Doug and will be mentioned later. You can see that the circuit is in fact really simple. There is a LED to simulate the compressor (with a resistor), and then the 1-Wire temperature sensor (with another resistor). The code is pretty simple too. Here's my latest fancy version: #include <OneWire.h> #include <DallasTemperature.h> #define COMPRESSOR 13 #define ONEWIRE 2 #define HIGHTEMP 4 #define LOWTEMP 3 #define SLEEP_SEC 10 // 220L Kelvinator is 85 watts #define COMPRESSOR_WATTAGE…

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Saturn’s Children

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I had trouble getting really into this book, although the story was interesting. I guess its mostly the Gibson-esque descriptions of a future world with plenty of assumed knowledge. However, I found the descriptions of the failed Mars missions deeply satisfying, and would love to see those covered in more detail. However, the story gets better as you go along, and I found the second two thirds of the book to be really good. It probably helped that I have an engineering background, because some of the descriptions are quite technical.

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Bolo!

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This book is a return to the short story collection style of Bolo book, with all of these short stories being written by David Webber. Unfortunately, most of these stories are not new: "Miles to Go" and "A brief technical history of the Bolo" appeared in Bolos 3: The Triumphant, and "The Traitor" and "A Time To Kill" appeared in Bolos 4: Last Stand. Only "With Your Shield" is new to me in this book. That one new story is a good one, although I think it helped that the Melconians had already been introduced in other short stories. I enjoyed it, even though there was only about 90 pages of new content in this book. [isbn: 1416520627]

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Last Human

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This is Doug Naylor's first solo book, after the breakup of his Red Dwarf partnership with Rob Grant. This book deviates pretty wildly from the plot line developed by the TV series, although it does use some of the ideas from the series. Often these ideas are used in such a different way that it would be annoying if you were expecting a novelization of the series. This book also has more characters die than is normal for Red Dwarf, and I felt that often the deaths were unneeded. Apart from that this was a good quick read. [isbn: 0140143882]

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The Dragonlover’s Guide to Pern

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I bought and read this book for the short story "the impression", which is ok but not fantastic. Overall the book isn't really my thing -- its mostly a potted history of Pern and a nearly exhaustive coverage of the various weyrs, holds and craft halls that inhabit the planet. To be honest, I'd rather learn that stuff as I read the series, instead of reading a summary. Overall I think this book isn't particularly great, although its nice to have read the short story at the right time in the sequence. Having just read Dragonsdawn, there are also some inconsistencies which grated a little (the use of HNO3 for example, and how much knowledge of the Oort cloud the survey team had string to mind as examples). [isbn: 0345412745]

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Dragonsdawn

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This book was similar to the other McCaffrey books I've read in that it felt like it lost its way in the middle for a bit. I'd been looking forward to this book for a while, because I really wanted to see the science fiction aspects of colonizing a new planet and developing a genetically engineered dragon explored. While this book did that, I don't think it focused on the elements I wanted to -- there was little discussion of the mechanics of either of these things, and instead a big sub plot about a jewel thief which was irrelevant and annoying. Overall, this book was ok, but not fantastic. [isbn: 0345362861]

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Bolo Strike

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There is a planet populated by humans which has been isolated for many years. In that time, aliens have come to rule the planet and treat the humans as slaves. Its pretty clear that they need liberating, right? What if you trash the planet in the process? What if they actually have the ability to defend themselves (something you didn't adequately prepare for)? Pretty standard bolo fare, and fun for all the same reasons as the others. I enjoyed this book, even if I am not a better person for having read it. [isbn: 0743435664]

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The Ship Who Sang

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This book is good science fiction, in the sense that it explores something which we are not ready to address as a society -- in this case, would profoundly disabled people prefer that we could replace their disabled bodies? What if the replacement wasn't humanoid? The book is pretty old though, and that shows in some of the elements of the story. I don't feel it detracts though. The book is also composed of a series of independantish by related short stories, which was a common publishing technique for science fiction in the 1960s. One story -- "Dramatic Mission" -- did throw me a little. Its just too out there conceptually, and actually kind of dull until about the last three pages, where the controller poses some interesting questions of Helva. I feel that perhaps the lead up could have been better though. [isbn: 0345297687] [award: nominee nebula 1969]

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