CC Kit Idea

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johngaltnh
 
Posts: 1
Joined: Wed Oct 08, 2008 11:02 am

CC Kit Idea

Post by johngaltnh »

I use microcontrollers and various stuff to solve sort of "one of a kind" problems, but I think my next problem is of the sort where others might find it useful; so it might be worthwhile to make it into a kit.

The problem: I have a chicken coop. I want to keep the water from freezing by turning on a light bulb positioned under the waterer (it's metal) whenever the temperature of the waterer is below 35F, and turn it off when the temperature is above 40F. Similarly, when the ambient temperature of the chicken coop itself is below 20F, I want to kick on one 250W heat lamp, when it is below 10F I want to kick on two of them, and when below 0F I want to kick on three of them.

In essence, you can imagine this as four temperature-controlled 120VAC outlets that are set to turn on (and off) at certain temperatures where one outlet is controlled by one sensor and the other three are controlled by another.

I can imagine a number of other uses for this besides chicken coops. For example, to keep pipes from freezing in certain locales, etc.

Presumably, to make this more generically useful I would have to make the set points user-definable. I think I can get close enough for government work just using a linear pot/voltage divider and ADC -- or, if I have enough code space, using a timing mechanism with an RC network to figure out the position of the pot.

The basics won't be rocket science. The temperature sensors will be MCP9700's read by the ADC lines on an AVR chip, and the relays will be driven by a '2803a darlington driver chip.

For myself, I'm planning to put everything but the relays and external controls on an arduino shield. (The temperature sensors will plug into that). Hardware-wise it should be straightforward enough -- 2 ADC lines, 4 digital I/O lines &c.

Two questions: Is it worth turning something like this into a kit (i.e. would there be enough demand for it) and would it be acceptable to make the kit available as parts and a diagram for how to hook them up on a shield?

magician13134
 
Posts: 1119
Joined: Wed Jun 13, 2007 9:17 am

Re: CC Kit Idea

Post by magician13134 »

It probably would not have a very high demand, you're one of one people I know with a chicken coop! (I take that back, my uncle has one, but it's empty, he's all cows and horses and stuff now). Anyway, this would be pretty simple to do with the Arduino, a thermistor and 4 relays. If you do do it, make sure your thermistor isn't right by the lights, that would not be great

eil
 
Posts: 440
Joined: Sun Aug 31, 2008 11:09 pm

Re: CC Kit Idea

Post by eil »

I've actually wanted to do this for some time. I have no chickens, though. What I'd like is a winter refrigerator.

Here's the rationale: In the winter, you spend a bunch of money to keep your house warm and then within that house, you have one area (the fridge) that needs to stay cool, so you spend even more money running a compressor and fan just to cool that one area back down again. Seems like such a waste, since running a refrigerator with a compressor and fan eats a non-trivial amount of power.

The solution? A big box that sits outside in the winter and keeps food cold because, well, it's cold outside. The only problem is that (in Michigan, at least) winter temperatures are often near or below freezing. In a well-insulated box, a light bulb or two should be enough to counter this and keep it from becoming a freezer, but it has to be turned on and off automatically based on the internal temperature of the box, just like the compressor on a normal fridge. (But in the other direction, and using far less power, of course.)

This seems like such a simple idea that it should be popular everywhere (especially with America's new "going green" fad), yet I've never heard of any implementations of it. Am I missing some key drawback?

Actually, I just thought of two. 1) You'd have to go outside to get your snack. We Americans are entirely too lazy for that. 2) Many households (such as mine) tend to keep a lot of food in the fridge so the outdoor box would have to be rather large and my porch doesn't have a lot of room to spare.

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macegr
 
Posts: 293
Joined: Fri Apr 04, 2008 4:46 pm

Re: CC Kit Idea

Post by macegr »

In Wisconsin we always used to keep stuff in our glassed-in porch, that was usually very cold but didn't go below freezing. Pies, soda, cooling fudge, etc. I knew a lot of people who did that; enclosed porches are pretty common there because it's a place to stomp off the snow and mud and take off your boots. Best of all, it's not ugly, and you don't have to think of a place to store it during the summer.

You have to consider the security aspect, too. If you plan to use it as your main fridge for the winter months, it's not an appealing idea to have random people walk up and steal your leftovers or drop disgusting things into the pickle jar. If walking outside was a turnoff, walking outside with a key to open the fridge is the deal breaker.

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