Alberto Smulders wrote:

> Hello,
>
> For remote sensing and controlling in a greenhouse, we want to use
> bi-directional data transmission over power lines, using very cheap
> hardware (microcontroller eventually with incorporated ADC and
> relays/triacs for controlling stuff), so we can chatter around small "black
> boxes" in the greenhouse where we need them, without lots of dedicated
> wiring to a central controller; all the "black boxes" under control by a
> central PC running Win95 or (maybe) Win NT.

X-10 and PowerLine/CEBus are implementation of such technology.
There been some articles in Circuit Cellar regarding these
implementations.

Intellon sells the interface chip needed to do PowerLine
implementation.  Its their SSC P400 Netowrk Interface Controller and
the SSC P111 Medial Interface IC.  You can get more information from
their web site, http://www.intellon.com.

Also, Circuit Cellar published a two-part article on a X-10 circuit.
It been about two years ago.  If you are interested in the exact
months, I can look it up.  The circuit was based upon a PIC chip.
I believe that their web site is http://www.circuitcellar.com.

Hope this helps,

Richard Rosenheim
rrose@accessnv.com