One of the great new features of the Circuit Playground Express is the addition of an infrared LED and infrared receiver. This allows you to use your Circuit Playground Express as an infrared remote control or to send signals to the Circuit Playground Express to make it perform various functions such as changing the pattern or colors of the NeoPixels.
The Adafruit_CircuitPlayground library allows you to control various functions on the Circuit Playground Express and in the latest version it has incorporated a specialized version of IRLib2. IRLib2 is a powerful library that allows you to transmit, receive, and decode IR signals using an Arduino or compatible microcontroller. It supports a large variety of protocols. These protocols are used by different manufacturers of consumer electronics products such as TVs, DVD/Blu-ray, and cable boxes. The specialized version of IRLib2 is incorporated into the Adafruit_CircuitPlayground library has been preconfigured for use with the Circuit Playground Express.
We have another Tutorial here in the learning system that teaches you how to use IRLib2 on other Arduino platforms. If you are interested in more details you can get IRLib2 directly on GitHub. That repository includes an extensive users manual with lots of details about the supported protocols and extensive information about how IR signals are transmitted and received.
In this tutorial we will give you a brief introduction to IR signals and show you how to use the IR features specifically of the Circuit Playground Express.