Make an Optical Disk Display

Every curious how DVDs work? Interested in learning some simple analog electronics? This Instructables will show you how to make an optical disk display project in only a few hours. What is an optical disk? An optical disk stores data/information and can be read or displayed using light. You will learn about basic analog electronics, basic electronic optics, and various basic electrical components. You will be making a fun encoder, turning a digital light interface into an analog signal that controls a 7-seg display.”