My Arduino demo sketch is a model of the human eye. It uses the light sensor as input, and displays how the human eye would respond to the given level of brightness. The pupil dilates to take in more light when brightness is low, and the pupil shrinks to take in less light when brightness is high. If brightness gets too high, the person is overwhelmed and begins to squint or close their eyes.

The video begins by showing how the eye responds to various lighting conditions. I cover and uncover the light sensor with the lights off, then do the same with the lights on. After the 50 second mark, I show how the eye is able to look by manually changing the number which represents the amount of light in the room. This way I can show how it appears at 0 (no light) and at 1 (maximum light).