Are c_idx and d_idx in non-volatile RAM? I'd prefer my fridge to continue working, without intervention, after a power outage.
There appears to be a defrost-cycle period between each opportunity to change the settings by one. Could take a while.
Sylvia.
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tDepends on the micro. Some can save to EEPROM. That's why i though about pots in the first place. Pots are non-volatile. We need an A2D to read from thermistor anyway, so perhaps using 3 channels A2D. One port for the defrost heater and one more for the compressor. One more set of decoder/LEDs for temp. settling. So, to do all the fridge control:
PIC32MX256DA206 (using 11 digital ports and 3 analog ports)
100K Pots (x3) 74XXX138 (x3) LED (x24) Thermistor 240V/5A AC relay (x2) etc.
I've taken apart a lot of things and I've never seen a power relay with 120 volt rated contacts. Do whatever you want, I'm done with this thread.
-- You can't have a sense of humor, if you have no sense.
Seriously, PICAXE 08M2 - 3 x 10 bit digital ports, configures and reads as 8 or ten bits with with a single "readadc" or "readadc10" command (IIRC) and 256 bytes eeprom reads and writes with simple single line instructions. PICAXE is the simplest and fastest solution to any one off that needs a little smarts and not too much speed bar none. If you need lots of LEDs one of the bigger PICAXE chips will do.
I have programmed (and still do) PIC's in assembler (very badly - I still do that very badly too), Microchip C, Swordfish Basic, and PICBASIC Pro. For speed, cost effectiveness and ease of producing a one-off PICAXE easily cleans the floor with all of them.
(I don't really like the guy who invented the PICAXE or his business model but it is a good product)
-- We have failed to address the fundamental truth that endless growth is impossible in a finite world.
"Moore's Law" fails when you get to one atom sized conductors (in practical terms we can expect it to fail before then)
"Moor's law" is about one, specific and small situation. By appealing to "Moore's Law" as a general solution you are burying your head in the sand.
-- We have failed to address the fundamental truth that endless growth is impossible in a finite world.
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I can do a one-off PIC32 faster than PICAXE. I don't like doing decimal bit maps in BASIC.
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Its a better idea to stop defrost cycle when the exchanger temp rises above freezing. Otherwie you're wasting energy, and at some point the machine will likely ice up.
NT
FWIW, those are oft-cited misconceptions. Media drones repeat them without understanding their basis.
The number is ~32 million, and these are people who do not have medical insurance. That is not the same as "extremely poor access" to care. Numerically, some 10-12 million of that figure are illegal aliens, and most of the remainder are young people who voluntarily choose not to buy it. Access is generally good to excellent.
60-odd % is the proportion of people who go bankrupt who, among their other bills, also owe money to their doctors. The number whose medical costs *caused* their bankruptcy is a small fraction.Last, everyone can get care. There are countless medical programs for the poor.
I personally have an acquaintance getting the full royal treatment, for cancer, for nothing. She's better than most at working the system, but it's there for people who need it, and seek it.
-- Cheers, James Arthur
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w tYes, we will need one or more thermistors or thermocouples to monitor the temperature.
The 'standard' self-defrost implementation has an additional thermostat on the cooling element, which trips open when the element reaches some predetermined temperature (11C on mine), and closes again at some lower temperature (0C on mine).
11C seems rather high, but I suppose it's intended to ensure that the entire element has defrosted, not just the part near the thermostat. It also means the thermostat need not be that accurate.Switching the cooling back on immediately after the thermostat trips off seems attractive, to avoid defrosting the stuff in the freezer, but I have some misgivings about the impact on the compressor of starting when the element is that warm.
It's not clear to me why the machine would ice up if the defrost cycle is left running too long.
Sylvia.
Well, I obviously can't say what you've see, but here's relay with 120V rated contacts.
Sylvia.
-- By admitting - ergo addressing the fact - that there _is_ a limit to the application of Moore's Law, your .sig: "We have failed to address the fundamental truth that endless growth is impossible in a finite world." is rendered invalid since you, at least, have not failed to recognize that endless growth is impossible in a finite world.
Mike said _power_ relay. The one in the url you posted is a signal relay.
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You could design a defrost system like was on the New Inventors last year. IIRC a resistive strip was placed in the freezer, a known voltage passed through it periodically and the resistance of it measured (heat causes resistance to rise, and the more frost/ice formed on the strip the longer it took to heat up and resistance to rise) and turn on the defrost system only when sufficient ice was detected.
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I have checked a few from my junk box, any that are intended to switch mains power and not signal circuits have a 240v rating. Many were out of junked US made equipment and made in Japan, Mexico or Taiwan.
As they are for the world market, I would think that most would be rated 240v.
One Japan made one that is UL rated has an inductive rating of 5a
240VAC and 0.5a at 120VDC for inductive loads.5A 120V and 32v for resistive loads.
The contact clearance is about 1mm.
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A lot of the modern ones use butane as a refrigerant so may be they do not want open contacts in the very remote case of leaks
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Did not see that but it may also be the case with the newer fridges.
I suppose it depends what one is trying to achieve. Clearly, it's wasteful of energy to heat up, and then cool, an element that doesn't have much ice on it.
On the other hand, keeping it that way means that the defrost cycle doesn't have to take long, which is helpful is one's primary goal is to keep the freezer compartment below a certain temperature.
Sylvia.
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