[Fabio Varesano's] new Arduino compatible board packs a full power punch in a ultra compact layout, measuring at 20.7×15.2 mm, the Femtoduino is probably the smallest 328 based Arduino compatible board around. Most of the staples are present, an QFN atmega328, an MIC5205 low dropout regulator good for a couple hundred milli amps, 16MHz ceramic resonator, reset, power indicator and pin 13 LEDs, but you will need to provide your own serial connection (FTDI, MAX232 etc) and another AVR programmer to get the Arduino boot loader onto the chip.
Since the board is small (smaller than a pro mini) it is not directly breadboard friendly. Even though the hole spacing is 0.05 inch, the size is large enough for “normal” wire to fit into fine, if you wish to use 0.1 inch spacing there is a handy break out board you can make where the Femtoduino just snaps in.
Everything needed to make one of your own is provided on the website, schematics, kicad files, bill of materials, Gerbers for both the board and the breakout board, though we would like to see this as a pre-made board soon, join us after the break for a video and see why.