RE: X10 replacement ?

["Ian Davidson" <ian@xxxxxxx>]

Hi Andy

Sorry for the delay in replying I've been out all day then got a message
I had to get a blood test, just got back in.

>This looks very interesting! What speed do your units operate at? iirc
X10 is 300baud.
>Any information on the protocol itself used to communicate with the
devices?

X10 send a 120Khz burst every zero crossing point of the mains so 50Hz
means a maximum of 50 Bits per second (50 Baud). X10 makes good use of
the bits so it only needs about 2 bytes worth but this means it is still
slow and limited. I believe it was invented in the 1970's and for that
time it is excellent I just feel that it is now too limited for what I
wish to do. My system communicates at 2400baud, but it packet length
varies slightly depending on the address being used etc but a packet
length of 12 bytes is usual.

>Can you request the status of a device to see if it's on of or dimmed?
You Bet you can. You can find out the status of the brightness, the rate
and the switch details. All commands are 16Bit CRC checked and Ack'ed to
confirm receipt of the message. If no Ack is received a series of up to
three retries is automatically actioned. The local switch also sends out
to any address the command it just gave again with the crc and retry.

>Looking forward to seeing some finalised units. Relay units could be
useful
>for things like controlling radiator valves. I really like the idea of
mains interfaced
>displays, temperature monitors etc... top stuff !!!
I have the hard work done, to make a relay unit just means cutting down
the dimmer unit really. One evenings work would see it done in prototype
form. The other stuff would be slightly longer but not to much. The
display I know works because I use an LCD attached for the Dev work.
Temperature etc should again be fairly straight forward, I already have
the 1 wire starter kit with the DS1820 etc I just need more spare time.
Even a door entry type system would be possible using Ibutton then
passing that via the mains to where ever it was needed.

>What are you going to call it?! IDXR? X101? 10X? c'mon, give us a clue?
Bloody good question, the only one I haven't got an answer for. All
suggestions greatly received.


>Really impressive stuff Ian! I hope you've also got ideas about
developing
>a stand alone controller (like Homevision) so that no PC is /required/
May be in time. The system as is operates without a PC. If the HA system
is down you loose the automation side but all local switches work as
normal (well the last command you told them to perform). You could even
have a small batch file send out a group ID that all units respond too
setting there switches to normal on/off. When you move house no one know
it was automated as the switches would be normal and work the same or
you could take it all with you as the wiring stays standard just the
ceiling rose to rewire back to standard.

>keep up the good work
Thank you

Ian D


*********** REPLY SEPARATOR  ***********

On 22/04/2003 at 21:54 Ian Davidson wrote:

>Hi All
>
>A long time since my last post but I have been reading all the group
>mail. Since I moved house last year I also started to install some X10
>modules (at the old house I had some basic home made modules and some
>home made RF linked kit) but soon stopped as they seemed so slow and
>unreliable.  A few months ago I decided to build my own modules for use
>around the house, all the lighting and some appliance modules etc.
>Although X10 is a very well established I didn't like it and decided to
>start from scratch. I know there are others (CBUS looks very good) but
>they either were to expensive or required dedicated cabling to each
>point (or both).
>
>Anyway I've now got to the point of needing to get some PCB's designed
>but thought I would ask people what they thought so far and if anyone
>could suggest any improvements before I started on the PCB's (Hate that
>job). Rather than explain everything here I've botched together a
>webpage to explain it so please have a look if you have the time and
let
>me know of any mistakes or improvements you can think of.
>
>http://www.galeforce9.co.uk/details1.htm
>
>I still have much to do especially on the PC software side but I should
>get there in the end.
>
>Thanks
>
>Ian D
>




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