> Soft stop would just be for elegance, fades away not dump you in
> the dark if you are out of range of PIRs  :-)

Ah, good idea. Perhaps a time delay (5 seconds ?) before the fade

> zc, opto isolated, don't like 240v potential down low voltage wiring :-(

Something like picture 2 here ?

http://home.clear.net.nz/pages/joecolquitt/txless.html

If you need to, use a scope and a PIC output signal to compare to
the input so the timing can be organised so that routines don't trip
over each other

> Not decided on the PBs yet, but they will be chosen for
> appearance not electrical performance, so some signal clean
> up may be a good idea

"hope for the best, plan for the worst", as they say ;-)

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