James Coggan gave a presentation on connecting devices with Firebase and Android Things. He discussed using Android Things to build IoT devices, integrating devices with Firebase for remote data and control, and using Nearby Connections for local device communication and data sharing without an internet connection. The presentation covered getting started with Android Things, common I/O interfaces, setting up Firebase projects, observing cloud data changes with LiveData, and a code example controlling an LED from a mobile device over Firebase.

1. James Coggan, MyDrive Solutions
Connect your Phone and Home
with
Firebase and Android Things
We are hiring!
https://www.mydrivesolutions.com/jobs
Q&A
sli.do
#thingstelaviv

2. A little bit about me..
James Coggan
Android tech lead
https://jamescoggan.com
@mad_team

4. What is Android Things?

5. Android + Internet of ThingsAndroid Things

6. The hardware
NXP Pico i.MX7D
Raspberry Pi 3 NXP Argon i.MX6UL
NXP Pico i.MX6UL

7. Development kits
NXP Pico i.MX7D Raspberry pi kit

8. Android

9. Android Things

10. What Android Things does support

11. What Android Things doesn’t support

12. Good to know
● Main application started on boot
● Permissions are free and set on reboot
● adb connect 192.168.1.111:5555

13. Why Android Things?
● Kotlin :)
● Maintained by Google
● OTA updates
● Android community
● Hardware agnostic
● Relatively cheap hardware
● Reusable code

14. Getting started
https://partner.android.com/things/console/u/0/#/tools

15. Getting started

16. Getting started

17. Supported I/Os
● General Purpose Input/Output (GPIO): Binary
● Pulse Width Modulation (PWM): Servo motors, DC motors
● Inter-Integrated Circuit(I2C)
● Serial Peripheral Interface (SPI)
● Universal Asynchronous Receiver Transmitter (UART)

20. Raspberry Pi NXP MX7D

21. val pioService = PeripheralManagerService()
try {
val pinName = "BCM6"
ledGpio = pioService.openGpio(pinName)
ledGpio?.setDirection(Gpio.DIRECTION_OUT_INITIALLY_LOW)
} catch (e: IOException) {
e.printStackTrace()
}

22. val pioService = PeripheralManagerService()
try {
val pinName = "BCM21"
button = ButtonInputDriver(
pinName,
Button.LogicState.PRESSED_WHEN_LOW,
KeyEvent.KEYCODE_SPACE)
button?.register()
} catch (e: IOException) {
e.printStackTrace()
}

23. override fun onKeyDown(keyCode: Int, event: KeyEvent): Boolean {
if (keyCode == KeyEvent.KEYCODE_SPACE) {
setLedValue(true)
return true
}
return super.onKeyDown(keyCode, event)
}

24. override fun onKeyUp(keyCode: Int, event: KeyEvent): Boolean {
if (keyCode == KeyEvent.KEYCODE_SPACE) {
setLedValue(false)
return true
}
return super.onKeyUp(keyCode, event)
}

25. val gpioForLED: String // Pin 31
get() {
return when (Build.DEVICE) {
DEVICE_RPI3 -> "BCM6"
DEVICE_IMX6UL_PICO -> "GPIO4_IO22"
DEVICE_IMX7D_PICO -> "GPIO2_IO02"
else -> throw IllegalStateException("Unknown
Build.DEVICE " + Build.DEVICE)
}
}

26. val gpioForButton: String // Pin 40
get() {
return when (Build.DEVICE) {
DEVICE_RPI3 -> "BCM21"
DEVICE_IMX6UL_PICO -> "GPIO2_IO03"
DEVICE_IMX7D_PICO -> "GPIO6_IO14"
else -> throw IllegalStateException("Unknown
Build.DEVICE " + Build.DEVICE)
}
}

27. val pinName = gpioForLED
ledGpio = pioService.openGpio(pinName)
...
val pinName = gpioForButton
button = ButtonInputDriver(
pinName,
Button.LogicState.PRESSED_WHEN_LOW,
KeyEvent.KEYCODE_SPACE)
...

31. Setting up Firebase
https://console.firebase.google.com
● Create a new Firebase project
● Add a new Android app to the project with your
package name: ie: com.jamescoggan.thingspresentation
● Enable anonymous login on (temporarily)

32. ● Setup a database
// Database
{
"light" : true
}
● Add the rules
// Rules - don’t expose your data for the world
{
"rules": {
".write": "auth != null",
".read": "auth != null",
}
}

33. // Base build.gradle for all modules
buildscript {
...
dependencies {
classpath "com.google.gms:google-services:$googleServicesClassVersion"
}
}

34. // mobile & things build.gradle
dependencies {
...
implementation "com.google.firebase:firebase-core:$playServicesVersion"
implementation "com.google.firebase:firebase-database:$playServicesVersion"
implementation "com.google.firebase:firebase-auth:$playServicesVersion"
implementation "android.arch.lifecycle:extensions:$androidArchComponentsVersion"
}
apply plugin: "com.google.gms.google-services"

35. // MainActivity.kt (Both modules - mobile and things)
override fun onCreate(savedInstanceState: Bundle?) {
FirebaseApp.initializeApp(this) // Move me to the Application class
val firebaseAuth = FirebaseAuth.getInstance()
val databaseReference = FirebaseDatabase.getInstance().reference
}

36. // MainActivity.kt
override fun onCreate(savedInstanceState: Bundle?) {
...
val databaseReference = FirebaseDatabase.getInstance().reference
firebaseAuth.signInAnonymously()
.addOnCompleteListener { task ->
if (task.isSuccessful) {
observeLightsData()
} else {
Timber.e(task.exception, "FirebaseAuth:failed")
}
}
}

37. // Light.kt
class FirebaseTables {
companion object {
val LIGHTS_BASE = "light"
}
}
data class Light(val light : Boolean)

38. class LightLiveData(val firebase: DatabaseReference) : LiveData<Light>() {
private val valueEventListener = object : ValueEventListener {
override fun onDataChange(snapshot: DataSnapshot) {
val newValue = snapshot.getValue(Boolean::class.java) ?: false
value = Light(newValue)
}
override fun onCancelled(error: DatabaseError) {
}
}
override fun onActive() {
firebase.child(LIGHTS_BASE).addValueEventListener(valueEventListener)
}
override fun onInactive() {
firebase.child(LIGHTS_BASE).removeEventListener(valueEventListener)
}
}

39. // Things Activity
private val lightsDataObserver = Observer<Light> { lightState ->
Timber.d("LightState changed: ${lightState?.isOn}")
led.setValue(lightState?.isOn ?: false)
}
override fun onCreate(savedInstanceState: Bundle?) {
...
firebaseAuth.signInAnonymously()
.addOnCompleteListener { task ->
if (task.isSuccessful) {
lightsLiveData.observe(this, lightsDataObserver)
} else {
Timber.e(task.exception, "FirebaseAuth:failed")

40. // Mobile Activity
override fun onCreate(savedInstanceState: Bundle?) {
...
toggleButton.setOnCheckedChangeListener({ _, state: Boolean ->
databaseReference.child("light").setValue(state)
})
}

44. Nearby
● Pub/Sub
● Send messages, files or stream data
● No need for server
● Peer to peer
● Wifi or BLE

45. Nearby

46. googleApiClient = GoogleApiClient.Builder(this)
.addApi(Nearby.CONNECTIONS_API)
.addConnectionCallbacks(object :
GoogleApiClient.ConnectionCallbacks {
override fun onConnected(connectionHint: Bundle?) {
startService()
}
override fun onConnectionSuspended(cause: Int) {
failed()
}
})
.build()

47. private fun startService() { // Android Things
Nearby.Connections.startAdvertising(
googleApiClient,
"appName",
"serviceId",
connectionLifecycleCallback,
AdvertisingOptions(Strategy.P2P_STAR))
.setResultCallback { result ->
when {
result.status.isSuccess ->
Timber.d("startAdvertising:onResult: SUCCESS")
else -> Timber.w("STATE_READY")

48. private fun startService() { // Phone
Nearby.Connections.startDiscovery(
googleApiClient,
"serviceId",
endpointDiscoveryCallback,
DiscoveryOptions(Strategy.P2P_STAR))
.setResultCallback { result ->
when {
result.status.isSuccess ->
Timber.d("startDiscovery:SUCCESS")
else -> {
Timber.w("startDiscovery:FAILURE
${result.statusMessage}")

49. private val connectionLifecycleCallback = object :
ConnectionLifecycleCallback() {
override fun onConnectionResult(endpointId: String?, result:
ConnectionResolution?) {
Timber.d("connectionResult from " + endpointId, result)
sendDataPayload()
}
}

50. // Phone
private fun sendDataPayload(email : String, password: String) {
val credentials = Credentials(email, password)
val adapter = moshi.adapter(Credentials::class.java)
val json = adapter.toJson(credentials)
Nearby.Connections.sendPayload(
googleApiClient,
currentEndpointId,
Payload.fromBytes(json.toByteArray())
)
}

51. private val payloadCallback = object : PayloadCallback() {
override fun onPayloadReceived(endpointId: String?, payload:
Payload?) {
val adapter = moshi.adapter(Credentials::class.java)
val credentials = adapter.fromJson(jsonString)
credentials?.let {
saveCredentials(credentials)
}
}
}

52. firebaseAuth.signInWithEmailAndPassword(email,password)
.addOnFailureListener { exception ->
exception.printStackTrace()
}
.addOnSuccessListener {
loadData()
}
}

53. Success!!

54. https://github.com/jamescoggan/thingspresentationn
● Common code in shared module
● Nearby
● RainbowHat:
○ Sensors
○ Led
○ Button
● Philips Hue (in progress)

55. Q&A
sli.do
#thingstelaviv

56. Feedback:
https://goo.gl/gwPxpY
Thank you!
https://jamescoggan.com
@mad_team