This is the Mechatronic Eye project I made for Halloween 2011. This video shows the (currently) six operating modes for the Eye, which are cycled through using a pushbutton on the side. Each time the mode is changed, the LED blinks the number corresponding to the mode (twice for mode 2, etc.)
0 - Iris open, LED off, MCU in sleep mode (this is basically 'off' mode).
1 - Iris closed, LED off
2 - Iris open, LED on
3 - Iris 1/2 open, LED on
4 - Iris closed, LED on
5 - Random iris position, LED on
This project does NOT use an Arduino. Arduinos are great, but would be total overkill for something like this.