I would also like to establish an open protocol based on RS-485, and
powerline.

There are several out there CANBUS, FIELDBUS, DEVICENET, LONWORKS,
PROFIBUS, HDLC, CMSA/CD, SMB/I2C/ACCESS, USB, IRDA, etc.

Some not as robust as others, but all not public domain, and many
requiring custom chipsets ie. CAN controllers, Neuron chips(LONWORKS).

What I am finding is that most are quite limited in the local nodes
they can handle.  ie. 32, 64, 127. (without repeaters)

As well as many other fallbacks in each.  I am struggling to select
one for a standard I am creating for a customer, and am about to
roll my own, but would rather just snarf up some ready built stuff with
readymade functions.(particularily for the PIC and PC)

I also have application for this in the test engineering field, as I
really would rather stay away from GPIB for my test jigs, but would like
to daisy chain on one port so I can test more than one product per pc
at the same time.

Craig

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Keith Howell
Sent: Friday, July 17, 1998 3:46 AM
To: PICLIST@MITVMA.MIT.EDU
Subject: Hi-fi and networked consumer electronics



Hi all.

I've noticed quite a few posts about people trying to roll-their-own
networks for various apps. I've had to do a small (but difficult) one in
my work project, a smart amplifier that you can plug in boards for
things like home cinema sound.

For now, the network is internal. However, if you could network
consumer goods then various exciting possibilities arise.

Question 1: What kind of clever things would you wish for?

Would you like your answering machine to wake up your PC to store
voice-mail on hard disk, then leave a text message on your hi-fi about
it? Or have your CD player and amplifier co-operating? Perhaps have your
phone messages accessible via the digital radio in your hobby den?

Question 2: How would you like to network them?

There are quite a few "home automation" schemes around, but they all
have pros and cons. Mains networks (e.g. X10) avoid the need for cable
but are slow and depend on reasonable clean mains. Radio networks also
avoid wiring but are expensive and they have trouble getting beyond the
room they're in. Most practical systems use Category 5 cable.

Bang & Olufsen kit can network, but it is proprietary. Meridian also
have one - this uses one RS232 for PC's to access the network (so that
they can download software upgrades for instance) but it is RS485
thereafter. Smart move, as this largely avoids +/-12V rails.

However, I'd like to come up with something as an open standard that
others can use (like MIDI) and robust against kit made by less well
built kit form other people. Note that MIDI is optoisolated too. It's
also cheap. CANbus has some merits, though this does restrict ones
processor choice.

I look forward to assimilating technological ideas
from the collective consciousness of the PIClist.