6 I/O Pins (2 are used for USB only if your program actively communicates over USB, otherwise you can use all 6 even if you are programming via USB). Power via USB or External Source - 5v or 7-35v (12v or less recommended, automatic selection). Support for the Arduino IDE 1.0+ (OSX/Win/Linux). The Digispark is shipped fully assembled except for the two included and easy to solder headers. The Digispark is an Attiny85 based microcontroller development board similar to the line, only cheaper, smaller, and a bit less powerful. With a whole host of shields to extend its functionality and the ability to use the familiar for Arduino IDE the Digispark is a great way to jump into electronics, or perfect for when for Arduino is too big or too much.