The Talk2 whisper nodes are low powered boards based on the Atmel AVR ATMega328p microcontroller. This board can be powered with as little as 0.9V. You can even run it o a CR2032 battery for a long time with correct coding.
The whisper nodes use a built-in RFM69W Sub-GHz RF module for wireless communication, which are a lot more energy efficient compared to 2.4ghz wifi for instance. In order to use the nodes with the internet you will need to set-up a base station receiving the RF communication from all nodes, the base station could be an arduino with whisper node connected.
For my base station I chose to use the esp8266 as a base station since I still had plenty of these from my “Test Setup ESP8266” I simply connected a whisper node through serial connection. Just connect pin1 & pin0 from the whisper node to the RX & TX of the esp8266.
I added codesamples to my latest post