Dataterm and other IHCs

[niavasha]

There was some Dataterm discussions about 10 years ago on the group, most seem pretty happy, but unsure on savings costs.

Ten years later, any one have any clue if it does save money on the bills ? Any other products out there that touch it or do better?

[Andrew Gabriel]

About 10 years ago, I started building my own home automation system, which includes intelligent heating controls. Back then, I would have guessed such things would be standard fit by now, but they actually haven't moved on very much at all in that period -- possibily a few more products, but still near to zero market penetration for the lot.

To be honest, I don't think IHC alone makes a lot of sense. You really need home automation, of which IHC is just one part, but fully integrated with the rest of the home automation.

The public doesn't seem to want it. If you add home automation or other perceived complex controls to a house at the moment, you reduce the value of the house, and that's on top of the high price you have to pay for such schemes in the first place. This hasn't stopped me, but it does mean I have done it with a view of ripping it all out if I needed to sell the house, and going back to your basic timeswitch and bimetallic thermostat.

[Tim S]

Andrew Gabriel coughed up some electrons that declared:

I think having some standards would help. X10 was good in that it was a standard and didn't need wires. But despite that, the lack of good heating controls was a problem (well, I never found what I would rate as a decent time/roomstat).

What you need are small inexpensive one-function devices that are easy to program and flexible.

eg for heating, you might have one roomstat+timer per room, or zone - but you'd want to be able to program one receiver to operate on its demand signal to open a radiator valve, *and* you'd want to be able to bind lots of them to one relay receiver to create a boiler demand signal - and so on.

Then you might want to be able to interrogate them all with a device that either logs stuff, makes it remotely available and allows master control - eg TXT home to turn the heating on whilst sitting on the train.

And the protocol should be open and standard so that lots of company and opensource hackers will make widgets.

So you could start with a few widgets to achieve something meaningful, then add more widgets later - and if someone didn't make a widget, you'd have the option of homebrewing that one device without having to make everything - or even better, another company would see a market and make it for you. A real mix n match lego system.

The bit rate and addressing capabilities of X10 were limited, but radio modules are cheap these days, so something running on one of the free radio bands with a standardised carrier, modulation and basic extensible protocol would be cool.

Problem at the moment is that many existing systems are prorietry, and tend to target "building control" which means hellishly expensive.

Cheers

Tim

[Jim]

There's been a lot of talk about making something like that based upon the Zigbee or Wibree or Z-Wave standards. As you have outlined, it can't really take off until a standard emerges which is truly open and useful: because the killer feature is compatibility between different brands.

It's an interesting technology, though: in theory you could get the cost and power usage of the transmitters down to the point where you could have switches run off a single AAA cell that would last years. So you could get rid of the insanity and expense of running high voltage wires down walls to lightswitches for low-bandwidth signalling.

And it would enable all sorts of cleverness in terms of control of lighting and heating at a lower budget, much like has happened with CAN-BUS and microcontrollers in car systems.

[Tim S]

Jim coughed up some electrons that declared:

Zigbee seemed over complicated at first sight, with it's ability to mesh and do fancy stuff. But, assuming that all happens in the module and the external interface is straightforward, if the devices become ubiquitous, then it won't matter as they'll be as cheap as chips eventually.

quid isn't a bad start - imagine if they were a fiver. A quid or two for a microcontroller and you really could have the lightswitches at a sensible price - especially as one common PCB could handle several switches, so 1-4 gang switches and push button dimmers would only need one identical PCB across the range. I'm thinking grid system, with one clever grid module which could take several cheap slave buttons wired in the side allowing a mix n match plate to be put together by anyone.

Indeed.

Better build some basic security in to the protocol though - otherwise the drive by hackers will have lots of fun turning off your lights (think wireless doorbells)

Tim

[Peter Parry]

We had one for 12 years and on an under floor heating system it worked well. It ran the heating effectively so there would have been some saving because of that.

Two years ago the Dataterm started to misbehave and their repair costs were quite high.

I replaced it with a Honeywell CM907 and a separate hot water controller. This combination is equally as effective as the Dataterm and was considerably cheaper.

[The Natural Philosopher]

Why reinvent the wheel? SNMP and http ovver whatever piece of wet string...you have.

Probably the easiest is to use the whole mains as ethernet, and hav individually addressable modules with web screens to 'set them up' and use snmp to switch them..

[Andrew Gabriel]

X10, being out of patent and being by far the cheapest technology of the family is probably still the only chance. Being a good technological solution isn't required, just being good enough.

You're looking at it as a network engineer. There are no network engineers in the building trade. Very few electricians are capable of installing home automation, or even quite simple home alarms. Those people need to be able to install whatever you come up with.

Now design something an unskilled builder can install and needs no setup/configuration at all (because there won't be anyone around with any skills to do that, especially not the home owner). You probably have a price ceiling of £100 max per item (e.g. a sensor or remote switch, plus the actual switching element, being less than £100 added cost over fitting the existing existing equivalents including labour and configuration charges). Again, X10 is probably the only thing that comes close.

[Tim S]

Andrew Gabriel coughed up some electrons that declared:

So no requiring that the user recompiles the firmware from source (after patching in 500 bugfixes) and TFTPs it in to their thermostat then?

That would be the Gentoo way :)

[niavasha]

Thanks for that, looks like a worthy challenger.

At the moment I've got a Horstmann CentaurPlus C27 which controls two zones and hot water. I presume I'd have to use two CM907 one for each zone and then a seperate hot water controller?

Any thoughts any one?

Thanks

[Peter Parry]

You would need one for each zone positioned appropriately as they obviously include the thermostat. The Centaur could be retained to control the hot water.

[niavasha]

Thanks much. I might replace the current remote stats with the remote room sensors that can feed into the CM907, the F42010972.