Hello I want to make a simple home automation project and I'd like to use an arduino uno for prototyping and later a atmega for deployment. I need some sort of a mesh communication method. I was thinking about the NRF51822 chip but I can't find any arduino libraries for it.
You can use the NRF51822 as module with AT firmware attached to Arduino. Then you need only the AT commands reference and some examples how to send AT commands and parse the response.
Or you can use the 32-bit ARM cortex-m0 micro-controller inside NRF51822 with Arduino nrf5 package. It requires a programmer/debugger hardware for sketch upload.