Arduino Cookbook, 3rd Edition

Using Displays

11.0 Introduction

Liquid crystal displays (LCDs) and LED displays offer a convenient and inexpensive way to provide a user interface for a project. This chapter explains how to connect and use common text and graphical LCD/LED panels with Arduino. By far the most popular LCD is the text panel based on the Hitachi HD44780 chip. This displays two or four lines of text, with 16 or 20 characters per line (32- and 40-character versions are available, but usually at higher prices). A library for driving text LCD displays is provided with Arduino, and you can print text on your LCD as easily as on the Serial Monitor (see Chapter 4), because LCD and serial share the same underlying print functions.

LCDs can do more than display simple text: words can be scrolled or highlighted and you can display a selection of special symbols and non-English characters.

You can create your own symbols and block graphics with a text LCD, but if you want fine graphical detail, you need a graphical display. Graphical LCD (GLCD) and graphical LED displays are available at a small price premium over text displays.

Graphical displays can have more wires connecting to Arduino than most other recipes in this book. Incorrect connections are the major cause of problems with graphical displays, so take your time wiring things up and triple-check that things are connected correctly. An inexpensive multimeter capable of measuring voltage and resistance is a big help for verifying that your wiring ...