William Chops Westfield wrote:
> This is California where it doesn't rain in the summer, so you need
> to water everything.  the house came with 36 zones of sprinklers,
> controlled by three separate 12-zone controllers (which seems to
> be near "as big as they come.")  They don't coordinate.  Their
> configuration is baroque (probably limited by the 256bytes of
> ram in an 8051) and entirely volatile.  I can fit a schedule
> that lists every freaking minute of the year in a $10 flash
> card these days, and a used PC or palmtop costs less than the
> price of single 12-zone controller at the gardening store (even
> neglecting that they seem to multiply like coat hangers around here.)
> It's all STUPID.  I can do better than that.  It may take me 10
> years of spare time, but I'm sure I can do better :-)

Sounds like a good application for CAN.  At slow enough bit rate (which you
can easily tolerate) you can wire CAN in combinations of star and bus
configurations with maximum node to node wire length in the 100s of meters.


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