Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "The setup() function runs only once every time the board is either reset or powered up."

A block of code is set as follows:

// Signal a quick LOW just before giving a HIGH signal
digitalWrite(3, LOW);
delayMicroseconds(2);

// After 2 micro-seconds of LOW signal, give a HIGH signal 
// to trigger the sensor
digitalWrite(3, HIGH);
// Keep the digital signal HIGH forat least 10 micro-seconds
// (required by HC-SR04 to activate emission of ultra-sonic
// waves)
delayMicroseconds(10);

// After 10 micro-seconds, send a LOW signal
digitalWrite(3, LOW);