I saw that the lowoower.h from RocketScream is somehow included in mysensors.
How can I power down with mysensors to low power?
Couldn't find an example.
Ok is sleep using internally the lowpower.h?
I am used to use the constants defined in period_t like SLEEP_8S.
Is there a good description how to use the low power state and interrupts?
Yes use sleep() . Take a look at the api.