This is the test setup for “Small Sensoria”. It is several LEDs being (mis-used) as light sensors connected to an Arduino. The USB cable connects them to a computer running a Processing sketch that renders the light intensities.
The values can be plotted linearly:
Next I am going to make the Arduino unit more independent by adding a Bluetooth shield, battery power, and wiring the LEDs up to it.
You can get the Arduino and Processing source code here: