I found a nice documentation about how to build an Arduino controlled light dimmer ( http://www.instructables.com/id/Arduino-controlled-light-dimmer-The-circuit/#step1
). They detect the zero crossing of the sinus wave by using interrupts. After a zero crossing is detected, a TRIAC is fired after a defined delay. So an interrupt happens every 10 ms.
In one of my projects I want to control the dimming level by temperature measurement. I want to measure some thermodynamic properties of different compounds and I need to heat the gas supply pipes and maintain a const. temperature (with PID).... I already build a PT100 that use two LTC2053 OpAmps and a LTC2400 24 bit AC/DC converter that communicates via SPI with Arduino. Is it possible to handle the 10ms interrupts and a SPI communication just with one Arduino? ...
cheers, Max : )