Re: Re: [Project] Lights was Foundations are in!

["James Hoye" <james.hoye@xxxxxxx>]

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> 1. Does EVERY lightswitch etc need to be TCP/IP enabled. As you have
already
> mentioned, the Rabbit modules are quite cheap for what they are, but
they
> still arent cheap. A light switch has very limited requirements even
for a
> multi-switch plate. A few buttons, a few LED's and possible an LCD
display.
> This is easily accomplished with a low cost PIC. A Lightswitch, even
if it
> controls other systems is still dependant upon other modules with more
> processing power and functionality.

Even conventional mains light switches could be used - suitable provision
could be made on the 'room controller' in the form of mains terminals (of
course, there a need for suitable isolation).  This would give simple
on/off
control only (as well as remote on/off via HA controller) - which may in
some instances be enough (outside security lighting)

> Room Controller - aka Dimmer Pack which would house the dimming
circuits
for
> the lights in a room plus relays for curtains etc. Keypads and sensors
in
> the room would communicate with the room controller via RS485 or
similar
> where all the keypads/sensors could be daisy chained on one CAT5 back
to
the
> controller.

Or a DS 1-wire bus?  Not an expert (yet) on either I'm afraid.

> Room Controller does not specifically mean 1 per room. It is a
> generic/working name for a unit with several channels of lighting
control,
a
> few relays etc. Some rooms such as a Home Theatre may need a
controller of
> their own whereas several bedrooms may share one controller.
> [...]
> Originally I suggested that these sub systems would be connected via a
> second RS485 bus back to the HA Controller. This is where I now
believe
> TCP/IP should come into the equation. That would give direct access to
the
> room controller via TCP/IP and would be totally independant of other
> controllers/equipment/computers in the house. The status of all
switches
and
> sensors could still be visible because the room controller would be
> communicating with them via its local bus.

This sounds ideal - a TCP/IP lightswitch in reality is a bit OTT.  Of
course, a TCP/IP master lighting console is another thing....  You could
use
it to control multiple 'room controllers' such as all lights on, all lights
off, light halls/landings/corridors...

> If a switch on a particular Keypad was needed to control something on
> another sub system no problem. The Room Controller in Room A detects
the
> keypress and knows that it is a message for
> Comfort/Homevision/AVcentre/whatever and sends it via TCP/IP to the
> appropriate sub system.

Yes.

> Whilst the ideal of every single device being TCP/IP enabled may seem
nice,
> I dont believe it is realistic until you can buy a low cost
Microcontroller
> that can provide a single chip solution. To do this the chip must
connect
> directly to a multidrop RS485 bus (negating the need for multiple
hubs),
> handle all the TCP/IP functionality through dedicated hardware (like
the
> onboard UARTS in some PIC's handle Serial comms) and have sufficient
I/O
> pins to interface to all the switches/displays. Some analogue input
might
> also be nice but most analogue commodities that need measuring such as
> volume/light/heat/humidity seem to be getting dedicated 1 wire devices
> developed giving nice digital values to work with. When such a
> microcontroller is available for a quid then having every device
TCP/IP
> enabled will be a reality.

Also to think about for lighting controllers:  a fire alarm input which
when
triggered will turn all lights on - I suppose this could be a small module
sitting on Ethernet that would broadcast all lights on when signalled.

It really does look as though things are starting to come together.  Keith,
another meeting would be handy (pizza would of course be incidental...!),
as
I know we've discussed this sort of thing in the past.

James H

James H




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