There was a very good article on PIC Triac control in an English
magazine - Electronics Today International, by a guy called Bart Trepak.
He's probably reachable through the net.

The only mystery to me is designing the choke required to suppress
interference - I don't know a formula for doing that.

> ----------
> From:         Ernesto Tolocka[SMTP:etolocka@ONENET.COM.AR]
> Reply To:     pic microcontroller discussion list
> Sent:         Wednesday, November 26, 1997 7:59 AM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      Re: inteligent house - network...
>
> Hi Ruben
>
> >> Another thing, is there anyone that has any ideas as to how to make
> a
> >> 'digital' light dimmer, with a pic? This could be nice for the
> above
> >> project....
>
> I have an idea, like a angle-control system with a triac: generate an
> interrupt synchronously with the AC supply. In every interrupt, start
> a
> variable delay timer,
> according to the 'light level'. At the end of the delay, turn the
> triac ON..
>
> Ernesto Tolocka
> Salsipuedes, Argentina.
>