In this chapter, you learned how to use controller widgets such as Slider, Step, zeRGBa, and Joystick with your Blynk app to control actuators with digital and virtual pins. Using virtual pins allows you to overcome the PWM pin limitation of the Raspberry Pi, as the Raspberry Pi has only one PWM pin, BCM_GPIO 18. You also used the software PWM library, which is the part of the WiringPi library used to define any GPIO pin as a PWM-enabled pin to work with controllers that have multiple outputs in merge mode.
In Chapter 4, Using Display Widgets, you will learn how to build applications with display widgets.
