Re: Hello

[Kevin Hawkins <yahoogroupskh@xxxxxxxxxxxxxx>]

Hi Biff...

What an interesting first post :-)

I guess I have a fundamental question - do you see the controller (
or an evolved version) being a device that performs one specific task -
in your example a central heating controller, and therefore in a HA
setup you might have several of these controllers each performing a
different role ?  Or do you see more of a master role , where you might
have a controller performing scheduling of events, logical interactions
between other devices and maybe some macro type facility, maybe one
master controller for several slave heating controls perhaps ?  I'm
thinking at the moment it's the former.  In which case I would encourage
an easy way of integrating the device within a parent control
application or standalone controller, and people all have their
favourites.   You need then to settle on just how to do this and as you
have Ethernet it seems obvious either to use a Telnet type socket comms
and plugins for the HA application or to use a protocol like xAP or xPL
for which plugins already exist.   If your hardware has the RS232 level
shifter then a serial connection remains an option but seems to not
maximise the controllers capabilities , it may however be easier  for
users to work with serial rather than a Telnet connection and may be the
only option for a hardware controller like HomeVision.  The
Telnet/serial protocol could be the same.   If possible I would
recommend that you do have an onboard web interface for configuration if
it's not too onerous a task,  which opens another possibility of an http
control interface.

xAP hat on...
I'm a great advocate of trying to allow all your HA devices to
operate without dependence on a PC application (ie embedded) and hence
my own personal preference for xAP.  xAP/xPL is just an easy yet
powerful model to use to get things all talking.     You can then layer
more complex control on top of this using your favourite PC HA
application as well so it's very flexible.  As you have to create a
control/eventing protocol of some form  anyway it's just one that's
there for you already should you wish.   There are emerging xAP embedded
controllers too now - like opnmax that runs on the Linksys NSLU2 and
even HomeVision,  a perennial UKHA favourite,  can integrate xAP devices
now using the embedded gateway.
xAP hat off....

Re the rest of your questions.  £19 for the base controller (£30
kitted
out) seems pretty affordable, and it's nice to have the option of a
cased version.  My preference would be for 1-wire but that's just
me...    If you do choose to support multiple endpoint sensors then you
have to decide again on the role of you device - as a centralised
climate control system with perhaps zone control ,  or multiple
individual controllers.  Weather station sensors... etc

Great project you're working on there, lots of potential I think  :-)

Kevin



bifferos wrote:
>
> The group instructions recommend an introductory posting for new
> members, so here goes...
>
> I am trying to produce a very cheap open-source Linux-based home
> automation controller using off-the-shelf components. I'm basing this
> on OpenWRT, because this gives you a linux ethernet enabled embedded
> system for 19 uk pounds (or 15 without USB). I've spent much of the
> last 6 months grappling with the Linux side of things, so haven't had
> time to look into home automation issues but I've now put together all
> the hardware for my central heating control project - consisting of
> Linux server with ethernet, i2c temperature sensor and reed relay, so
> everything can now be controlled by Linux - total cost < 30 quid so
> far. (My boiler thermostat switches an AC 24v line @ a few mA, so no
> need for expensive mains relays).
>
> As I was looking into how to produce the web interface for this system
> I decided at that point that I might be re-inventing the wheel. I
> have a choice now - either add my web interface and complete the
> stand-alone project, or add compatibility with one of the home
> automation systems and use *that* user interface.
>
> I have many questions for the group, sorry for putting them all in one
> post: What should this system be compatible with? xAP? xPL?
> SNMP??? How would people use such a system? Are there cheaper ways
> to achieve this? Is there demand for creating a PCB with the
> temperature sensor bit? Should I switch to using 1-wire instead of
> i2c? Would people be interested in a (modified) router pre-loaded
> with HA software, and if so, what should it do?
>
> best regards,
> -biff.
>
> PS: Currently I don't have an HA web site as such. All my stuff is
> on sourceforge, and is just general stull about Linux on the BR-6104K
> hardware. Here are some links if people are interested:
>
> Idiots guide to setting up OpenWRT:
> http://linux-adm5120.sourceforge.net/openwrt/idiots/
> <http://linux-adm5120.sourceforge.net/openwrt/idiots/>
>
> basic temperature sensing:
> http://linux-adm5120.sourceforge.net/openwrt/i2c/
> <http://linux-adm5120.sourceforge.net/openwrt/i2c/>
>
> And any source I write goes here:
> http://linux-adm5120.svn.sourceforge.net/viewvc/linux-adm5120/
> <http://linux-adm5120.svn.sourceforge.net/viewvc/linux-adm5120/>
>
>