Slides from my presentation at GDG Munich Android meetup on 24.01.2017

1. Android Things
Egor Andreevici
@EgorAnd

2. https://android-developers.googleblog.com/2016/12/announcing-googles-new-internet-of-things-platform-with-weave-an
d-android-things.html

3. ● Build connected devices using familiar tools, such as Android SDK and
Android Studio
● Google Play Services & Google Cloud
● Flashable image + SDK (Developer Preview)
Android Things

4. Android Things Platform - https://developer.android.com/things/sdk/index.html

5. ● Peripheral I/O API
○ GPIO, PWM, I2C, SPI, UART
● User Driver API
○ Inject hardware events into the framework
Things Support Library

6. ● Missing core packages
○ e.g. ContactsContract, MediaStore, Settings etc.
● Displays are optional
● Subset of Google Play Services available
● No runtime permissions
● No notifications
Behavior Changes

7. Hardware: Turnkey Solutions

8. ● Certified development boards
● SoMs (System-on-Modules)
○ SoC, RAM, Flash Storage, WiFi, Bluetooth etc.
● Board Support Package (BSP) managed by Google
Hardware

9. Supported boards - https://developer.android.com/things/hardware/developer-kits.html
Intel® Edison NXP Pico i.MX6UL Raspberry Pi 3

10. Coming soon - https://developer.android.com/things/hardware/developer-kits.html
Intel® Joule™ 570x NXP Argon i.MX6UL

11. Rainbow HAT - https://developer.android.com/things/hardware/developer-kits.html

12. ● Hardware Attached on Top
○ Seven multicolor LEDs
○ Four 14-segment alphanumeric displays
○ Three capacitive touch buttons
○ Blue, green and red LEDs
○ Temperature and pressure sensor
○ Piezo buzzer
Rainbow HAT

13. Raspberry Pi 3 + Rainbow HAT:
Getting Started

14. ● 8 Gb or larger SD card
● HDMI display + cable
● Ethernet cable
● SD card reader
Flashing the Image: Requirements

15. ● Download and unzip the latest preview image
○ https://developer.android.com/things/preview/download.html
● Write the image to the SD card
○ Instructions for Linux, Mac and Windows
● Insert the SD card into the Raspberry Pi
Flashing the Image

16. Android Things Launcher

17. Connecting via ADB
$ adb connect <ip-address>
connected to <ip-address>:5555
or
$ adb connect Android.local
if host platform supports Multicast DNS

18. Connecting WiFi
$ adb shell am startservice
-n com.google.wifisetup/.WifiSetupService
-a WifiSetupService.Connect
-e ssid <Network_SSID>
-e passphrase <Network_Passcode>

19. Demo App

20. https://blog.egorand.me/making-rainbow-hat-work-with-the-android-things-2/

21. ● Handle touch button clicks
● Change text on the alphanumeric display
● Play a melody using the buzzer
● Blink RGB leds along with the melody
Rainbow HAT Demo

22. https://www.youtube.com/watch?v=TErot2KaY6w

23. Declaring Dependencies
dependencies {
provided 'com.google.android.things:androidthings:0.1-devpreview'
compile 'com.google.android.things.contrib:driver-button:0.1'
compile 'com.google.android.things.contrib:driver-ht16k33:0.1'
compile 'com.google.android.things.contrib:driver-pwmspeaker:0.1'
...
}
app/build.gradle

24. Declaring Dependencies
dependencies {
provided 'com.google.android.things:androidthings:0.1-devpreview'
// compile 'com.google.android.things.contrib:driver-button:0.1'
// compile 'com.google.android.things.contrib:driver-ht16k33:0.1'
// compile 'com.google.android.things.contrib:driver-pwmspeaker:0.1'
compile 'com.google.android.things.contrib:driver-rainbowhat:0.1'
...
}
app/build.gradle

25. Creating Manifest
AndroidManifest.xml
<application ...>
<uses-library android:name="com.google.android.things"/>
…
</application>

26. Creating an Activity
RainbowHATDemoActivity.kt
class RainbowHATDemoActivity : Activity() {
…
}

27. Declaring the Activity in Manifest
AndroidManifest.xml
<activity android:name=".RainbowHATDemoActivity">
<!-- Launch activity from Android Studio -->
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
…
<activity>

28. Declaring the Activity in Manifest
AndroidManifest.xml
<activity android:name=".RainbowHATDemoActivity">
…
<!-- Launch activity automatically on boot -->
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.IOT_LAUNCHER"/>
<category android:name="android.intent.category.DEFAULT"/>
</intent-filter>
<activity>

29. Instantiating driver classes
RainbowHATDemoActivity.kt
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
buttons = Buttons()
display = Display()
buzzer = Buzzer()
leds = Leds()
...
}

30. Creating the Buttons class
Buttons.kt
class Buttons(private val buttonDrivers: List<ButtonInputDriver> = listOf(
registerButtonDriver(BUTTON_A_GPIO_PIN, KeyEvent.KEYCODE_A),
registerButtonDriver(BUTTON_B_GPIO_PIN, KeyEvent.KEYCODE_B),
registerButtonDriver(BUTTON_C_GPIO_PIN, KeyEvent.KEYCODE_C))) {
…
}

31. Creating the Buttons class
Buttons.kt
val BUTTON_A_GPIO_PIN = "BCM21"
val BUTTON_B_GPIO_PIN = "BCM20"
val BUTTON_C_GPIO_PIN = "BCM16"

32. Raspberry Pi 3 + Rainbow HAT Pinout - https://pinout.xyz/pinout/rainbow_hat

33. Creating the Buttons class
Buttons.kt
private fun registerButtonDriver(pin: String,
keycode: Int): ButtonInputDriver {
val driver = ButtonInputDriver(
pin = pin,
logicLevel = Button.LogicState.PRESSED_WHEN_LOW,
keycode = keycode)
driver.register()
return driver
}

34. Creating the Display class
Display.kt
class Display(private val display: AlphanumericDisplay =
AlphanumericDisplay(DISPLAY_I2C_BUS)) {
init {
display.setEnabled(true)
display.clear()
}
…
}

35. Creating the Display class
Display.kt
fun displayMessage(message: String) {
display.display(message)
}

36. Processing button events
RainbowHATDemoActivity.kt
val MESSAGES = mapOf(
KeyEvent.KEYCODE_A to "AHOY",
KeyEvent.KEYCODE_B to "YARR",
KeyEvent.KEYCODE_C to "GROG")

37. Processing button events
RainbowHATDemoActivity.kt
override fun onKeyUp(keyCode: Int, event: KeyEvent?) = when (keyCode) {
in MESSAGES.keys -> {
display.displayMessage(MESSAGES[keyCode]!!)
true
}
else -> super.onKeyUp(keyCode, event)
}

38. Creating the Buzzer class
Buzzer.kt
class Buzzer(private val speaker: Speaker =
Speaker(SPEAKER_PWM_PIN) {
…
}

39. Creating the Buzzer class
Buzzer.kt
fun play(frequency: Double) {
speaker.play(frequency)
}
fun stop() {
speaker.stop()
}

40. Creating the Buzzer class
Buzzer.kt
init {
stopRunnable = Runnable { stop() }
}
fun play(frequency: Double, duration: Double) {
speaker.play(frequency)
stopHandler.postDelayed(stopRunnable, duration.toLong())
}

41. Creating the Leds class
Leds.kt
class Leds(peripheralManagerService: PeripheralManagerService =
PeripheralManagerService()) {
…
}

42. Creating the Leds class
Leds.kt
private val leds: List<Gpio>
init {
leds = listOf(
openGpio(peripheralManagerService, LED_RED_GPIO_PIN),
openGpio(peripheralManagerService, LED_GREEN_GPIO_PIN),
openGpio(peripheralManagerService, LED_BLUE_GPIO_PIN))
}

43. Creating the Leds class
Leds.kt
private fun openGpio(service: PeripheralManagerService,
pin: String): Gpio {
val led = service.openGpio(pin)
led.setDirection(Gpio.DIRECTION_OUT_INITIALLY_LOW)
return led
}

44. Creating the Leds class
Leds.kt
fun setLed(led: Int, on: Boolean) = with(leds[led]) {
value = on
}
fun toggleLed(led: Int) = with(leds[led]) {
value = !value
}

45. Integrating Buzzer and Leds
RainbowHATDemoActivity.kt
private fun playMelodyWithLeds() {
playbackRunnable = Runnable {
buzzer.play(NOTES[noteIndex].toDouble(), DURATIONS[timeIndex] * 0.8)
leds.setLed(Leds.LEDS[ledIndex], on = true)
leds.setLed(Leds.LEDS[prevIndex(ledIndex, Leds.LEDS.size)], on = false)
if (noteIndex == NOTES.size - 1) {
// close
} else {
playHandler.postDelayed(playbackRunnable, DURATIONS[timeIndex].toLong())
// increment indices
}
}
playHandler.post(playbackRunnable)
}

46. Integrating Buzzer and Leds
RainbowHATDemoActivity.kt
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
...
playMelodyWithLeds()
}

47. Closing resources
RainbowHATDemoActivity.kt
override fun onDestroy() {
...
arrayOf(leds, buttons, buzzer, display).forEach(Closeable::close)
super.onDestroy()
}

48. ● Android Things - https://developer.android.com/things/index.html
● Samples - https://developer.android.com/things/sdk/samples.html
● Driver Library - https://github.com/androidthings/contrib-drivers
Where do we go from here?

49. What will you build?

50. Thanks!
Egor Andreevici
Software Developer at 1&1
@EgorAnd
+EgorAndreevich
https://blog.egorand.me