Now i have done:

-schematic and pcb design,

-build first prototype of controller board (not tested with oven yet)

-make small board with triac & optotriac to control heater (not tested yet)

-start writing the code; hardware looks nice; encoder, display, internal sensor, max6675 with thermocouple works.

-software menu structure

TODO now:

-implementation of menu in software

-implementation of calculate temperature from internal temperature sensor (inside Atmega)

-configuration Timer1 to drive speaker

-configuration Timer2 to make 1s interrupts

-calculate temperature change rate (derivatide dtemp/dt)

-test triac

I'm waiting for new themocouple from eBay, cause one i'm using now have huge metal end, and it can make problems to mount in the oven.

It's possible that the software will be to big for atmega88, and i change to atmega168/328.