The ATmega328P microcontroller requires 4.5 - 5.5 V dc when operating at 16 MHz.
Diavolino can be powered from a FTDI USB-TTL-5V cable, if you hook up the wire jumper that connects that power source to the board's "Vcc" line.
You can also power the board through a 3xAA or 3xAAA battery box, or through a plug-in power supply. For most situations that require wall-plug power, we recommend to use a 5 V power supply directly. If you have a specific reason to use a higher voltage wall wart (e.g., 9 V), then you'll also have to provide a voltage regulator to make the 5 V supply for the microcontroller.
Diavolino kits are available with two configuration options: a optional bundled battery holder and an optional set of socket strips.
The battery holder is a 3xAA box with cover and switch. The battery holder has almost exactly the same footprint as the Diavolino board, and you can stick it on with double-sided foam tape if you're so inclined. It's a great setup for easy portable projects.
The socket strip set is a four-piece set of header sockets, two each 6-pin and 8-pin, that allow the board to interface with many existing Arduino accessories.
An extended introduction to Diavolino is available here
, including the release of the Diavolino design files under an open source license.