Ok, so that's clear !
this answers a lot of questions !
Now that would make the whole thing a lot easier to do, no need for zero-crossing detection, just PWM driven should work.
No it won't.
Clear !
in fact there do exist dimmer boards that take PWM input. I think the have an ATtiny on board (could be another controller), which reads the PWM input and then handles the zero crossing and phase cutting part.
Also clear ! My original thought was to do the zero-crossing using the method advised in the instuctable link i posted, but see if i could control/dim multiple outputs. I would only need 1 zero-crossing detection to drive several Triac's
With the full cycle length at 10ms, i figure the time required to switch a pin will be negligible.
Now the question remains, will the digital dimming of the bulb work, or will the circuitry on the inside of the bulb complicate matters (the youtube showed dimming with an old style analog dimmer..)