Now that we've  built a project with Johnny-Five and Raspi-IO, it's time to tackle GPIO expanders and PWM outputs, and build an interactive project with an RGB LED. We'll also learn more about the Johnny-Five REPL, learn how a PWM pin works, and use this knowledge to control an RGB LED from the command line.

The following topics will be covered in this chapter:

• Looking at the LED and LED.RGB API
• PWM pins and GPIO expanders
• Bringing in other node packages with color
• The Johnny-Five REPL