C H A P T E R  6

Light Intensity Sensing

In this chapter you will learn how to sense the intensity of light in your close environment. In order to do that you will need another new component, called a photoresistor or light dependent resistor (LDR). I will explain the operating principle of this component later in the section “The Parts.” But first you'll need to understand the description of light itself.

So what is light, anyway? It surrounds us everywhere in our daily life. The complete ecosystem of our planet relies on light. It is the source of all life and yet most of us have never really bothered to understand what light really is. I am not a physicist and don't claim to offer the best explanation of its physical principle but I want to at least provide a brief description of what light is to give you a sense of the goals of this chapter's project.