Although small in size, great in capabilities. The Digispark ATTINY85 Mini USB Development Board is similar to the Arduino but cheaper and smaller (of course a bit less powerful). With a whole host of shields to extend its functionality and the ability to use the familiar Arduino IDE, this board is a great way to jump into microcontroller electronics.
Complete USB Development Board Cheap Enough to Leave in a Project. If you have never heard of the Digispark ATtiny board before, it may take you more than a moment to understand its full power and potential. So read this carefully:
Firstly, its a 20MHz, AVR 8-bit microcontroller with 8 KB flash, 512 bytes of RAM
You get up to 5 GPIOs, 4 ADCs, 2 PWMs, 1 SPI, and 1 I2C[*]
Secondly, its fully compatible with Arduino
Thirdly, it can be directly programmed via USB without needing any other programmer!
And finally, it is available at a cheap price!!
The Digispark is shipped fully assembled except for the two included and easy to solder headers.