Wouldn't this be cool...?

[toasty]

Good point about the light switches, but no regs breached I'm afraid, the light switches contain 10v signalling only back to the DMX dimmer racks under the stairs!

The SMS modem I use is a Siemens TC35i see here http://www.telefon.de/images/big/siemens_tc35i_terminal.jpg

It's not very big, but they are quite ££££, but 100% reliable, and of course I use it to send also.

As for SMS in the car park, I can actually browse over gprs, and see the temps of the house , and then decide whether or not to put the heating on based on that, although to be honest, it's becoming less frequent now as the house is starting to 'learn' (more about that later) when I will or won't be home!!! Quite spooky really! And the boiler is so big 140,000 btu in a small house that the heating kicks in really quickly.

Thanks for your interest.

 

[toasty]

Linux and Solaris mate, Not sure how much power it all uses, but not too bothered either. Might cost say £100 or so per year, but this is an unfair representation as most of the energy is turned into heat, so I get the benefit of using the heating less. So it probabaly costs less than you think. As for reliability, on good hardware, I've got linux boxes at work with uptimes of over 2 years. So it isn't a problem.

 

[PaulAH]

Well Toasty, that looks like the dog's oojits. Apologies for confusing it with a sales pitch. You're obviously proud of it and we can see why. Two questions (maybe more later )

Does the computer have to be on 24/7 to keep it all running? Can't see any signs of EEPROM or such.
EDIT: That point mentioned by others while I was writing. Put it another way: Have you looked at an NVRAM alternative or modification?

Why did you hard-code the program rather than use their GUI?

You also sound like the kind of guy who would appreciate Oilman's analogy of the flatulent fly. It was the 1/100 degree bit that also made me think it was marketing flannel.

 

[toasty]

No sales pitch I can assure you, I'm a techy, couldn't sell if I tried. I wrote my own code because I wanted to build the whole lot end to end, I did the wiring, the design, even made the dimmer switch controllers, plumbed the heating, painted the walls, so it makes sense I think to write the software. Don't get me wrong it's not all just lines of code, there is a web gui (also available over GPRS/WAP) which I can use to monitor/control (comes in handy with the cctv also)

1/100 degree C, well I got a bit carried away there, it does report to 2 decimal places, but it's actually nearer to 3/50's of a C (not all numbers are possible, i.e it skips a bit) but it is amazingly accurate in terms of room temp, walking past the lightswitches definately causes a fluctation in temp.

At present yes, I have 3 machines constantly on, only one for the homeautomation though, in time I want to write the whole lot in C and run on an imbedded controller, but still got to finish tiling the kitchen and generally finish the boring stuff first.

I just love all this stuff, the graphs you can get out of it are amazing too, If I plot room temp over a few weeks, you can actually see the heating effect of the sun rise in the morning, and the time at which it rises slowly changing through the seasons!! Brilliant!! Also, best of all, I can tell when the good lady is in the lounge and freak her out by flashing the lights etc... (she loves that!)

I'll dig out some graphs and post them later,

 

[toasty]

See attached graph, http://xs.to/xs.php?f=209-231.gif&h=xs53&d=05445

This is the temps of

yellow - Dining Room
blue - Bed 1
pink - Lounge

On Jul 29 to Aug 20 (days of the year 209 - 231) of 2005

You can see that on day 223 we had the aircon on quite a bit in the lounge and bedrooms (but not the dining room) and the corresponding temp difference is appreciable.

Note also, no heating used during this time, so the temp variation is purely natural.

 

[PaulAH]

Fascinating. Two more questions:

12 temp sensors, how many zone valves? It would get rather expensive having a motorised valve for each!
(Supplementary: There are electrically controllable TRVs - found Honeywell T850 on the www - but this is analogue, incremental 8-24v. Can't find any UK prices either. Anyone know anything about them?)

What happens if you're out and the good lady wants to hit the heat? Is she a programmer?

 

[toasty]

Hi,

I have 3 zone valves, upstairs, downstairs and hotwater. They are about £40 each, just normal Honeywell 240v on-off valves. (V4043 28mm) I think the ones you are referring to are blenders, so they take hot and cold and pump out something in between.
I then have electric underfloor heating in most rooms and some additional aircon which can go hot or cold.

If the little lady wants the heating on, then she can do it via the web page, or text or I can do the same for her, but as I say, the system is pretty smart now, it keeps the house at a fairly constant 18 downstairs and 17 upstairs during waking hours, and about 3 C less if we are out. At night it goes off, unless it gets really cold.

Yeah 12 sensors, but 2 are used for the flow and return boiler water temp and another does the outside temp. I also have one under the stairs where I keep all my equipment (I also have the Sky+, tv, audio, dvd etc... distributed so there is an awful lot under there) probably 20-30 plugs!! so it gets quite warm there (the boiler and 300litre mains pressure hot cylinder is there too) so I keep an eye on the temp there and if it gets too toasty then there will be an extractor fan to get a breeze going - at present I just leave the door ajar!!

Still lots to do, and I'm still tweaking it, but I think it's proved that it's possible so over the next few months it'll get better and hopefully be as efficient as any home system can be.


Out of interest, when I first put the system in, there was no feedback between the temp sensors and the heating, so I had to operate the heating by running a script or flicking a switch, i.e it didn't come on automatically. I'd be at work and get a call saying 'can we have the heating on for a bit?' I noticed fairly quickly that humans are very accurate when it comes to guaging temperature when they are cold. 18 seemed to be the trigger, any colder than that and I'd get a call, but once the heating was on, even 24C wasn't considered too hot.

With this in mind, I now keep the house at 18 if it goes below this, then on comes the heating, and once it gets to 18.4 it goes off. This doesn't take long at all in terms of boiler time, probably 5-10 mins. To get the room to 20 however takes appreciably longer, so I'm sure there is a saving to be made by just keeping the house temp slightly above what is perceived as cold - rather than spending a fortune keeping it at 21 like most people seem to.

 

[ChrisR]

Presumably she smiles at the face recognition kit and the system gets the hots - or does she have to get her kit off?

Eeee when I were a lad it were different. Anyone remember wheelbarrows? They were the things plod in NI used to blow up Ford Cortinas with too much fertilizer in the back. They were crude r/c robots, a bit like a shopping trolley on steroids. On the back was strapped an Acorn Atom. 6502 processor whizzing along at 1 Meg, built in assembler though and that was its jewel. The printer port was fine for output commands, as long as you only needed left, right, stop, go, go bang. Built in feature was that the r/c had a tendency to interfere with the output commands if you were too close. Safety feature Sir.

Sometime later, had to switch in a modem on a remote, dedicated phone line if a main comms link went down. There wasn't anything you could buy to do it. We could design something, but to plug into the phone lines it would have needed approvals and there was no time. So we used an Ansafone with the usual speaker, and a mike, to a tone decoder. So, no connections to the BT circuits, but by "getting through" and pressing beeping buttons one end we had outputs the other, to do what we needed. We thought we'd sell it and make our fortunes. Everyone and his dog suggested using it to control CH, but then the same people all thought it wasn't worth the effort. What went wrong?

The gui would have been a bit more difficult then...

 

[ChrisR]

Oh if you need neat zone valves, the sort of things used on UFH where there are lots of loops, I've got a cat with some in which are way cheaper than Honeywell. They do 24v or mains ones and have an auxilliary switch like a normal 2 port. They actually work by heating an internal trv head so they're not quick but they are silent. I'm sure you could control (PWM ?) the volts to control the degree of opening.
I was going to do a building full of bedsits with them with a programmable stat in each room, but the sparkies wanted too much to do the wiring!

email in profile

 

[toasty]

I didn't know about those Chris, they sound interesting, I guess you can't get 22 or 28mm ones though? I'm assuming they are 15mm which is fine for a room or two, but perhaps too small for a whole floor.

Agreed about the price of honeywell valves, although they do (3 port mid position excepted) seem to last a good long while.

 

[PaulAH]

I think the ones you are referring to are blenders, so they take hot and cold and pump out something in between.

I was thinking more of valves working on the same principle as a TRV. They bolt straight on to the rad. I ain't no plumber but, looking at the datasheet of the Honeywell, I guess they use a wax regulator like a TRV but have an additional (thermostatically-controlled) heating element that forces the wax to expand and reduce the flow through the rad. Also deduce the action is analogue.

Since your control is digital (in the either-on-or-off sense), presumably you'd activate it by putting 24v up its jacksie (or none).

Could one of you experts put us straight on this? ChrisR - is that the kind of thing you were suggesting? Are they hard-to-get (can't find any UK prices on the internet)?

One more for Toasty: How flexible are your programmable settings? Could you, for instance, tell it you want Bedroom 1 at 18deg between 7-8.30am, then off all day, then up to 19deg between 6-7.30pm, then down to 16deg until 10.30-12 when you want it 20 deg; and so on for bedroom 2, 3 etc.

Actually you've already answered that by saying you've only got three zones. But with individual rad control and your sensors, which must give an analogue signal (thermo-resistance devices?), could you achieve this through your own code and/or the GUI supplied?

 

[ChrisR]

Paul stick your email in your profile and Ill contact you with info - or email me.

 

[toasty]

The gui is infinitely settable, so yes, you can profile the temperature over time for any room.

As you say, I don't have enough zones to do each room with the central heating separately, but it's funny, in a quite small house, especially when the doors are open, you can't have much difference in temp between one room and another, so I'm not sure how much more flexibility I'd have with a zone valve per room (which I could still have as the cabling and pipework is compatable)

I'll post more later, but another really interesting thing is the flow and return water temps to the boiler, you'd be amazed how they change depending on delta T between in and out and also depending on how many zones are open.

 

[Stoday]

Wouldn't one programmable thermostat per zone, such as the Danfoss TP15, be cheaper, simpler and more flexible?

I'm not knocking toasty. Of course, this option was not available when he first built his system.

 

[toasty]

Not really mate no, how would that give you remote access and the sort of intelligence my system has?

I'll be the first to agree, my system is over complicated and over the top in every way, I'm the only person I know with a 28mm ringmain for the heating in a 3 bed semi!!

but my system is almost flawless, the things I can do are limited pretty much only by the software, a couple of programmable thermostats won't know if I'm home or not, and certainly cannot accept a text message, or text me when the garage is sub 10 degrees C.

As I say , not for everyone, but my system is really awesome, I've yet to meet someone who having seen it isn't totally impressed. Normally the browsing the settings/status from the pub over gprs does it, if that doesn't then just texting the heating and hearing the machinery work first hand has the desired effect!