I designed and built a device that can read paper tape with colored bands on it. The order in which the colors are read determine the bit pattern that comes out. A transition from red to green results in a 0 for example.

Source can be found here: https://github.com/keoni29/ColorData

With the current setup the string "Hello World" is about 1m long. I will experiment with different sensor placements and light gaps. My goal is to make the color bands thinner.