All -

It turns out you can NOT do what I had proposed...
hardwire a controller directly to the PowerRise
headrail, nor can you combine headrails on one
IR receiver.

The reason has to do with the way the IR eye is
connected and what it does. For reasons having
to do with power savings (default is that unit
is battery powered), the pins do multiple things...
the processor pin checks the state of the IR receiver
but also switches to an output pin when the processor
is sleeping (not checking IR status)... so wiring
headrails together creates a ground loop without
additional circuitry.

You can't connect the units directly to a controller
either as the IR eye is sending demodulated data
to the headrails, not simple up/down requests
or modulated IR codes.

So the best solution for now is to tie standard
IR emitters directly to the IR receivers... but
I'm hopeful Hunter Douglas is hearing these requests
and considers coming out with an interface to
help us automators...

--josh