Thanks much this thread, PaulS and Pico, I got this working at least some way. Now I've Mega which has W5100 ethernet to connect Cosm, and with 433Mhzh transmitter to control Nexa by using it's webserver, and now also nRF24L01+ to read temperatures from Nano with nRF24L01+ ds18b20. This works ok but code looks bad, I think I need to use interrupts, more studying 