I believe the BeanDuino is the smallest complete development platform in the world.

The BeanDuino is an ATtiny85 based microcontroller development board similar to the Arduino line highly inspired by DigiSpark , BeanDuino is hardware compatible with Adafruit Trinket / Gemma but due to restriction of selling boards with adafruit vid/pid you we can't sell boards wit gemaboot, you can replace yourself.

I believe the BeanDuino is the smallest complete development platform in the world.

Specifications:

• Support for the Arduino IDE 1.0 and later (OS X, Windows, and Linux)
• Built-in USB
• 5 I/O pins (2 are used for USB only if your program actively communicates over USB, otherwise you can use all 5 even if you are programming via USB) or 6 I/O pins if you dissable reset fuse
• 8 KB flash memory (about 6 KB after bootloader)
• I2C and SPI (vis USI)
• PWM on 3 pins (more possible with software PWM)
• ADC on 4 pins
• Internal temperature sensor
• On-board PB1 led - no shield required !!!
• Keyboard or other HID devices emulation (mouse, gamepad ...)
• reset is enabled you can program this board with USBASP or Arduino via ISP you can easy replace/repair/remove bootloader
• slim design 11x20 mm
• breadboard compatible