Embedded temperature controller...

Controller is the easy part. Wiring all the sensors and actuacters is the difficult part. How do you plan on commuicating between sensors, actuacters and the controller?

linnix skrev:

1-wire or X10.

I focus now on finding a good embedded controller with at least 4 channels and a good data base and intuitive webinterface.

regards

geir

There are X10 modules for passing digital on/off data. I have not seen any module for analog data such as temperature sensors.

OK, find one. No sure how it works with the rest.

This allows the threshold to be altered by anyone. I want to control everything from the computer, a dual display for current and preset temperature would be nice though, but no requirement

geir

Centrally controlled air cons are crap.

Thermostats in each room are the only successful way and many aircon companies make them and have done for 50 or more years. Stop reinventing the wheel and let an expert help you.

John G.

But such systems aren't just simple duct work. At the very least a multi-room controller involves controllable registers.

I would bet that Geir doesn't have a lot of money to burn.

...Jim Thompson

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| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
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 I love to cook with wine     Sometimes I even put it in the food

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Whatever way you look at it, central control will never provide the comfort of distributed thermostats and both require duct work of some sort to actually change the temperature. I agree the OP is likely tring to save money but should realize it may be the wrong way to achieve a good result. And professional A/C suppliers are likely to be better value in the end.

John G.

IF installed at the time of erecting the building. After the fact can be really expensive.

...Jim Thompson

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| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
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| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |

If we knew what we were doing, it wouldn\'t be called research...
                    -- Albert Einstein

There are retrofit systems that create multiple zones from one central heat a/c source. They involve installing some sort of damper for each zone. This is going to be the big cost item (if individual zone controls don't already exist).

From that point, the zone thermostats, central controller, etc. are simple and existing technology. They come loaded with features that will guarantee your scratching your head and pouring over operating manuals for months.

One interesting system I saw on a home improvement show involved controlling the air to each room with a system of inflatable bladders that were pulled into the ductwork. Each had an air line that was routed back to a pressure/vacuum control manifold. Upon a command from a wireless zone t'stat, the controller would start the furnace or a/c and then deflate or inflate the bladders depending on whether a particular zone needed or did not need air flow.

--
Paul Hovnanian     mailto:Paul@Hovnanian.com
------------------------------------------------------------------
A limerick packs laughs anatomical
Into space that is quite economical.
        But the good ones I\'ve seen
        So seldom are clean,
And the clean ones so seldom are comical.

Doesn't sound like a long-life system to me :-(

...Jim Thompson

--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
     It\'s what you learn, after you know it all, that counts.

Looking at the way the system was installed, it appears that if a bladder springs a leak, it would be pretty simple to pull another one through the ductwork. Snaking the tubing in the first time was time consuming.

All of the zone thermostats are r.f. to the central controller. I was thinking about designing small, motorized dampers* that would fit just inside each register, also r.f. linked to a controller. Since they'd need more power than a thermostat, I figured a little propeller driving a generator in the air flow would keep their batteries charged.

*You don't actually need motors. The dampers can be driven open or closed by the airflow by moving their pivot point relative to the center of aerodynamic pressure. A small solenoid could do the job.

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Paul Hovnanian     mailto:Paul@Hovnanian.com
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Broken pipe. Command flooded basement.

John, I take it you have never investigated the cost of those duct and register controls. I have. you can figure about an order of magnitude in cost increases over a standard set of ducting. Electronics (as in thermostats and controls) are cheap, but mechanically operating duct controls are expensive!

The system I was looking at would basically divided my house into three 'zones.' Trying to do it room by room is just expensive insanity!

Charlie

You also need to add a 'diverter' to the system, that diverts extra air flow not needed by the fewer ducts, back to the supply side of the fan. Otherwise, you blow those balloons right out the duct! 8-)

Charlie

PS: Those balloons aren't cheap, either!

With it likely that Obama's "development of alternate energy sources" is going to double my electric bill, I think I'd better be looking into replacing my 15-year-old "heat pumps" with something more sophisticated/efficient.

Servo-controlled registers shouldn't be all that hard to implement on your own... unless you're as dumb as AlwaysWrong or Slowman.

Fortunately my house is already well-insulated... I make it thru the Winter with rarely more than a night or two of heat required.

"Diversion to supply side" sounds like it could be implemented simply with another duct with a controllable register??

Of course my system would not utilize a single uP ;-)

And maybe we _will_ have global _cooling_, beneficial to us CONSERVATIVE desert rats ;-)

...Jim Thompson

--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
 I love to cook with wine     Sometimes I even put it in the food

Hi Jim, The diverters I studied were all mechanical. Basically, as the pressure reached some value, it forced open a damper between the two sides. It functioned pretty much as a pressure regulator.

Of course, all this stuff is real sheet steel, so it isn't really cheap. When you add the motorized dampers for zone control, that is when the real expense kicks in.

Some of them were basically on/off, which consisted of a spring loaded flap and a latch. When you wanted it closed, it released the latch. Air flow raised the flap to block that register or zone. It only would re-latch if you stopped the air flow. Not good if your system wants to add flow to a zone that is already stopped. You have to shut down, wait for the presure to drop, the spring to catch, and then you could start up again with the new load setup.

Sounds like an MCU sort of operation to me!

Charlie

How about a couple of solenoids to open/close dampers, thermostatically controlled, OR all thermostats to the central unit (AND'd with pressure sensor... exists already on my big systems.)

...Jim Thompson

--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
 I love to cook with wine     Sometimes I even put it in the food

Hey, I never said how small or how to divide the AIR system, all I suggested in the beginning was that central control by a computer was not too clever and a better way would be local thermostats that actually knew what area was hot or cold.

However the decisions are made there will be similar costs involved in controlling the air delivery.

My house is 3 zones and one thermostat and if I think I need a change, I change a zone switch. That's the way it was when I came here and it works fine ,for us.

John G.

Exactly, that is the level of complexity that comes across. Of course a solenoid takes real power to operate, it has got to move that 'heavy' damper... 8-)

Charlie