$5.$ Automatic rice cooker

I have a very nice rice cooker. I can put the rice and water in it in the morning, and

set it to start cooking at$,$ say $6$pm in the evening. It turns on automatically, and

when the rice is cooked, it switches to $$keep warm$$ mode. $-$ How does it control

when to turn on$?$

$-$ What type of sensor$($s$)$ and actuators do you think are inside this machine?

$-$ How would you sense when the rice is cooked?

$-$ How can the rice be kept warm for up to $12$ hours?

$-$ Such cookers can also be set to cook different food types $($rice$,$ congee, fish...$).$

How is the logic for so many functions controlled?