Re: [ha] wired home network using CAN

Steve Letkeman (
Wed, 25 Aug 1999 18:46:06 -0600

>Hi Steve,

Hi Lars,

>(so we CAN "lovers" meet here too ;-) )

As soon as we convince these users to go with CAN, we
can complete our evil plan of taking over the world...(oops,
did that go out to everybody?.....)

>I'm with you to a 100% and I also (as some might have read my
>earlier posts) don't mind running seperate wires and use CAN,
>since I have also worked with CAN since 1993 and just love
>Right now I'm looking at the possibility to have a very
>inexpensive node for this kind of purpose and it should
>be able to update it through FLASH etc. I do not want to
>go direct into the component selection I have made yet,
>but it will be inexpensive per node.
>I currenly use the C505C/C515C (an 8051 with CAN) and
>also the stand alone CAN controllers SJA1000 and 82527.
>This new node will be using the SJA1000, but I'm also waiting
>for the first samples of the Microchip standalone CAN
>controller MCP2510 or something like that. It is an SPI
>18pin SOIC CAN controller.

Can you build something cheaper and smaller than a C505C?
The C505C is my choice for the smaller projects from now
on but I'm still using a number of HC11's with the 82527.

>With CAN it is also possible to run things like "intercom"
>from one are in the house to the other,

I have been thinking about that. An intercom with an LCD
and a CAT-5 cable running voice and CAN and power. You
plug in any number of nodes and they annouce themselves
to the rest. When you want to use the intercom, you just choose
the name from the list and talk. Could also imploy an open
mic to receive voice commands.

also have smart nodes
>that operate for them self and send out info. e.g. an temp-
>sensor can send out (without asking) the temp each second
>and the CAN bus fic that with priority it self. then the
>nodes who are interesting in that temp value catch that
>message and use it, one could be a PC logging temperatures,
>another a simple LCD for looking at the temp, another controling
>heaters etc. CAN is very easy to deal with once you get
>hang of it.
>LAWICEL Phone : +46 (0)451-50750
>Lars Wictorsson Fax : +46 (0)451-50750
>E-mail: WWW :
>Embedded hardware/software together with 8051/C16x/AVR and
>smart distributed I/O with Controller Area Network (CAN).

Well said. I think the key is to having some sort of open protocol
that allows you to add any device to the network. What you do with
that device will be up to the individual nodes that are smart
enough to do something useful.

I was thinking about adding a section to my web site that outlines
my system and providing some downloadable protocol specs.

I am willing to provide some programming and documentation
and some circuit boards to this endeavour.