How to put arduino in sleep mode? I need to put arduino in sleep mode. I did not find the library avr/sleep.h . From where to download it.
avr/sleep.h is part of the compiler. You don't need to download it.

There are other libraries that act as a wrapper to it to make life easier:


https://github.com/lowpowerlab/lowpower
https://github.com/rocketscream/Low-Power