We will create a doorbell circuit using an active buzzer and an RGB LED. Since we have not discussed RGB LEDs before, we will take a quick look at this amazing little electronic component. We then write a simple test program, using our Raspberry Pi, that will light up the RGB LED and sound the active buzzer.
Wiring up our circuit
What is an RGB LED?
An RGB LED is really just three LEDs in one unit: a red one, a green one, and a blue one. Almost any color may be achieved by applying electric current at varying power levels across the selection of input pins. The following is a diagram of such an LED:
As you can see there are red, green, and blue pins, plus a negative pin (-) . When an RGB LED has a negative pin (-), it is...
