In its basic form, you just need the Atmega microcontroller, the crystal and 2 caps. A good idea is a 5V voltage regulator as well so you can use power sources bigger than 5V. The rest of the stuff on an Arduino Uno is not needed on a final project. Our Skeleton Duino is designed for that, but…….
We also needed a very low power consumption unit that can work from a coin cell battery for over a year. Hence this Diet Duino.
This board includes the ATMEGA328P-PU IC, a led (that can be powered programmatically if you have to) and a very low energy imported voltage regulator
Diet Duino Features:
There is no other board I know of that only consumes 16mA current by default and with sleep mode about 3 uA.
You can read all about this in our block post: Diet Duino, Arduino low energy consumption for battery powered projects
Something to mention is that there is no USB downloader, you can read more about it in the Skeleton Duino review here.
This unit is regulated at 3.3V regulated. It is important to keep this in mind for your projects. Many sensors do operate on 3.3V like temp/humidity sensors, DS18B20, most gyroscopes, accelerometers etc. but some don’t.