- 1 Introduction
- 2 Table of Contents
The main theme of this book is constructing Arduino projects that focus on sciences. In particular, this book has a very strong “green focus.” What will make these projects possible are sensors, which are devices that respond electrically to a physical change. Often this response is a change in resistance. For example, a flex sensor will vary its resistance based on how much bend is applied to it. Essentially, the sensor converts one analog (physical) condition to another analog (electrical) condition, such as temperature to resistance or impact pressure to voltage. By itself, a microprocessor (which lives in a digital world) cannot understand analog values. Resistance or voltage means nothing to a microprocessor. We need some way to convert these values into the ones and zeros of computer language. At this point, I think we need to define how a microcontroller such as the one built into the Arduino board differs from a microprocessor. In fact, a microcontroller is a microprocessor. However, it has several key differences from the one lurking inside your laptop or desktop.
A microcontroller has had several useful peripheral devices built inside the chip casing, along with the CPU. A microcontroller has RAM, ROM, serial ports, and digital inputs and outputs. All these might be familiar to you already. After all, your personal computer has all the same devices. However, it is important to note that these peripherals are built into the chip instead of sitting on the side. Therefore, they are much more limited than their desktop PC counterparts. Where a traditional PC might have gigabytes of RAM, a microcontroller might have only a few kilobytes. There is one peripheral device built into the microcontroller that we will focus on again and again throughout this book: the analog to digital converter, or ADC for short. As its name implies, the ADC connects the analog world to the digital world, converting the signals into something the CPU can understand and work with. Before moving on, let’s take a moment to look at the ADC more closely.