I've evaluated LON, CAN, MODBUS, etc.  and nothing compares to CEBUS.

http://www.cebus.com  Check it out, you'll be glad you did.

The powerline stuff is starting to exceed 10Mbit/s, blowing away the 120
bit/s of X10, and there are physical layer specs for RS485, RF, IR, etc.

The problem of custom chips is still there, but the price is reasonable,
and there are at least a couple sources.  Also, there is huge buy in
as this is supposed to be the new home automation standard.  Lucent,
Cutler Hammer, and Microsoft, to name a few.

CEBUS packets allow the addressing of 0xFFFF homes with 0xFFFF nodes,
sending 256 bytes data per packet.

The other neato thing is the use of contexts.  ie.  A TV will have volume
up/down power on/off channel up/down  pip on/off etc.  A light switch will
have power on/off dim up/down.  Thus your packetization is as simple as your
device and doesn't require a big micro implementing 17 software layers to turn
on a light bulb!

For an example product, see http://www.intelogis.com  They make a powerline
peer to peer networking solution for sharing data between 2 computers and
sharing a printer.  10Mbit over power line, $99 for the package.  Too good
to be true?


Craig



> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Barry King
> Sent: August 5, 1999 8:28 AM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: LON and CAN
> 
> 
> > > Anybody using the LON these days?
> 
> No.  I looked at it seriously too, both for home and commercial use,
> but concluded that its 1) too complicated and 2) too proprietary, and
> therefore 3) too expensive.  In turn, the critical mass of equipment
> which conforms is NOT there.  Nothing like a second source to keep
> you honest and keep costs low, LONworks has none.
> 
> I, too, have hacked various home control systems, and wished for
> some backbone protocol that would be cheap enough that small
> companies could build around.  Something as simple and cheap as
> X-10, but that worked.
> 
> X-10 is so lousy in some applications, that it falls into the
> not quite expensive enough catagory.  Is very old tech, and cost
> performance is no longer good enough.
> 
> I like the fact the LONworks defines several media and how to
> interconnect them.  Its important to be able to mix IR, RF, wired and
> Powerline, because most of us can't afford to start over.
> 
> There is a newsgroup for home control, comp.embedded.home or some
> such.  Anybody here follow it?  Any consensus on an emerging
> standard?
> 
> > The CAN bus looks attractive, what pitfalls await the hapless
> > > developer, will I get screwed blind by some accountant, lawyer,
> > > vampire (previous two occupations rolled into one) wanting their
> > > royalties and requiring expensive proprietary tools?
> 
> I *thought* CAN bus was an open standard, attempting to be the
> automobile internal LAN.  (So the door lock computer can chat with
> the left rear tire computer, ad nauseum.)  Can anyone confirm or
> deny that its open / liscense free?
> 
> I'll bet there's plenty of CAN expertise on forums about Motorola
> micros, since Motorola was an early adopter / developer of CAN, and
> their high end microcontrollers have built-in CAN bus peripherals.
> 
> >
> > EDN just ran a story about "Home Networking" protocols,
> > which -- since they were being marketed in that direction --
> > included some protocols that were traditionally used in
> > industrial applications, such as LONworks.
> 
> Well put.
> 
> > After reading the article, I had the overwhelming reaction
> > that this home networking stuff was in dire need of an
> > "open source" type solution.
> 
> Yes!  My reaction too.  I'll bet there is an emerging standard
> amongst home-control hackers.  I'm betting on RS-485 half duplex
> or its analog (you should pardon the expression) on powerline
> carrier.  But maybe since 10baseT is getting so cheap... Nah. ?
> 
> I agree with Bob that if a good system was promoted using the
> "open source" (and "open schematic"? for the hardware) model, it
> might take off.  But early fragmentation kills these things, so
> that's why I want to know what others are doing right now.
> 
> Its time to go hit the 'net newsgroups and the web sites for the
> doorbell, alarm, high end stereo, and automatic sprinkler
> manufacturers.  Many of these guys are small, and in reality I think
> they will drive the market for real home control that can be cheap,
> extendable, and reliable.
> 
> Easy for me to say, I have babies at home.  One hobby at a time :)
> 
> ------------
> Barry King, KA1NLH
> Engineering Manager
> NRG Systems "Measuring the Wind's Energy"
> Hinesburg, Vermont, USA
> www.nrgsystems.com
>