Introduction

LEDs in Parallel

LEDs can be used to light objects or to alert the user about the operating conditions of a device. Light-emitting diodes are easy to use and they come in a variety of shapes, sizes, and colors, as shown in Figure 4-1. The Arduino has a dedicated tiny LED wired to pin D13. By uploading the Blink sketch to the Arduino, you can check its electrical operation. Unlike the ordinary light bulb, LEDs must be wired properly for them to work. In this chapter, you will learn how to wire two LEDs to the Arduino, as shown in the block diagram in Figure 4-2. The LED projects in this chapter will also use Make:’s MakerShield, but you could use another Arduino-compatible prototyping shield. To add a little creativity to the LED projects, you will learn how to build an interactive toy using an ordinary piece of cardboard.