In this chapter, we have learned about the Android Things architecture, and then worked with a lot of different hardware components: LEDs, buttons, buzzer, alphanumeric display, sensor reading, and LED strip, with lots of examples and coding guidelines.
Although all the components seemed identical, we have used four different communication protocols: GPIO, PWM, I2C, and SPI.
The Rainbow HAT meta driver has abstracted us from these differences, but as soon as we move away from it and into using other components, we will need to know which protocols they use to communicate and how to wire them, even if it is just to know which pin to connect them to.
If we flip the Rainbow HAT, we can see the specs of each of the components:
- LED Red, Green, and Blue: BCM6, BCM19, and BCM26
- Buttons A, B, and C: BCM21, BCM20, and BCM16
- Piezo: PWM1
- Alphanumeric display (HT16K33): I2C1 0x70...
