[Anton Minashkin] Random Musings on the Android Things

Presentation from GDG DevFest Ukraine 2017 - the biggest community-driven Google tech conference in the CEE.

Learn more at: https://devfest.gdg.org.ua

Transcript

1. Random Musings on the Android Things Anton Minashkin Developer @ EPAM
2. #dfua Android Things Android based platform for IoT
3. #dfua Android Things
4. #dfua Things Support Library • Peripheral I/O API • User Driver API
5. #dfua Behavior Changes • UI • One application • Core application packages • Support for Google services
6. #dfua Behavior Changes • UI • One application • Core application packages • Support for Google services
7. #dfua UI • same UI toolkit • application window occupies the full real estate of the display • no system status bar or navigation buttons • display is not required
8. #dfua Behavior Changes • UI • One application • Core application packages • Support for Google services
9. #dfua One application • one app with Home activity • Home activity will be launched automatically on boot • must contain both CATEGORY_DEFAULT and IOT_LAUNCHER intent filters
10. #dfua One application ... <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> ...
11. #dfua ... <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> ... One application
12. #dfua Behavior Changes • UI • One application • Core application packages • Support for Google services
13. #dfua Core application packages • Standart suite of System Apps is not included • Avoid using common intents • Avoid using next content providers:
14. #dfua Core application packages CalendarContract ContactsContract DocumentsContract DownloadManager VoicemailContract MediaStore Settings Telephony UserDictionary
15. #dfua Behavior Changes • UI • One application • Core application packages • Support for Google services
16. #dfua Support for Google services Supports a subset of the Google APIs for Android
17. #dfua Support for Google services General rule: APIs that require user input or authentication credentials aren't available to apps
18. #dfua User-Space Drivers Managed by Google Managed by Developers
19. #dfua User-Space Drivers User drivers are components registered from within apps that extend existing Android framework services.
20. #dfua User-Space Drivers They allow any application to inject hardware events into the framework that other apps can process using the standard Android APIs.
21. #dfua Device Driver Types • GPS • HID (Human Interface Devices) • Sensors • Audio
22. #dfua Device Driver Types • GPS • HID (Human Interface Devices) • Sensors • Audio
23. #dfua Device Driver Types: GPS The GPS user driver allows your app to publish updates to the device's physical location through the Android location services.
24. #dfua Device Driver Types: GPS The framework only supports a single source for GPS location data. You cannot register multiple GPS drivers.
25. #dfua Device Driver Types: GPS ... // Create a new driver implementation mDriver = new GpsDriver(); // Register with the framework UserDriverManager manager = UserDriverManager.getManager(); manager.registerGpsDriver(mDriver); ...
26. #dfua Device Driver Types: GPS ... manager = UserDriverManager.getManager(); manager.unregisterGpsDriver(mDriver); ...
27. #dfua Device Driver Types: GPS public void handleLocationUpdate(String rawGpsData) { // Convert raw data into a location object Location location = parseLocationFromString(rawGpsData); // Send the location update to the framework mDriver.reportLocation(location); }
28. #dfua Device Driver Types: GPS public void handleLocationUpdate(String rawGpsData) { // Convert raw data into a location object Location location = parseLocationFromString(rawGpsData); // Send the location update to the framework mDriver.reportLocation(location); }
29. #dfua Device Driver Types • GPS • HID (Human Interface Devices) • Sensors • Audio
30. #dfua Device Driver Types: HID Input user drivers provide an interface for apps to inject events into Android's input pipeline
31. #dfua Device Driver Types: HID • 30+ input sources • deliver events to Foreground Activity
32. #dfua Device Driver Types: HID // Create a new driver instance mDriver = InputDriver.builder(InputDevice.SOURCE_CLASS_BUTTON) .setName(DRIVER_NAME) .setVersion(DRIVER_VERSION) .setKeys(new int[] {KEY_CODE}) .build();
33. #dfua Device Driver Types: HID // Register with the framework UserDriverManager manager = UserDriverManager.getManager(); manager.registerInputDriver(mDriver);
34. #dfua Device Driver Types: HID // A state change has occurred private void triggerEvent(boolean pressed) { ... KeyEvent[] events = ... if (!mDriver.emit(events)) { Log.w(TAG, "Unable to emit key event"); } }
35. #dfua Device Driver Types: HID // A state change has occurred private void triggerEvent(boolean pressed) { ... KeyEvent[] events = ... if (!mDriver.emit(events)) { Log.w(TAG, "Unable to emit key event"); } } synchronously | all or nothing
36. #dfua Device Driver Types • GPS • HID (Human Interface Devices) • Sensors • Audio
37. #dfua Device Driver Types: Sensors • ~30 Sensor types • ...and custom types as well • supports Sensors with sleeping mode
38. #dfua Device Driver Types: Sensors The data from these sensors is delivered through the same SensorManager APIs as the built-in Android sensors
39. #dfua Device Driver Types: Sensors The framework polls your driver periodically when listeners are registered for sensor updates
40. #dfua Device Driver Types: Sensors driver should return UserSensorReading containing the current sensor data.
41. #dfua Device Driver Types: Sensors UserSensorDriver mDriver = new UserSensorDriver() { ... @Override public UserSensorReading read() { ... return new UserSensorReading(new float[]{...}); } };
42. #dfua Device Driver Types: Sensors UserSensorDriver mDriver = new UserSensorDriver() { ... // Called by the framework to toggle low power modes @Override public void setEnabled(boolean enabled) { if (enabled) { // Exit low power mode } else { // Enter low power mode } } };
43. #dfua Device Driver Types: Sensors UserSensor accelerometer = UserSensor.builder() .setName("GroveAccelerometer") .setVendor("Seeed") .setType(Sensor.TYPE_ACCELEROMETER) .setDriver(mDriver) .build();
44. #dfua Device Driver Types: Sensors UserDriverManager manager = UserDriverManager.getManager(); // Create a new driver implementation mAccelerometer = ...; // Register the new driver with the framework manager.registerSensor(mAccelerometer);
45. #dfua Device Driver Types: Sensors FUN FACT: ServiceManager contains a lot of different constants, including: • GRAVITY_DEATH_STAR_I (3.5303614E-7) • GRAVITY_THE_ISLAND (4.815162) • LIGHT_FULLMOON/NO_MOON/CLOUDY
46. #dfua Device Driver Types: Sensors FUN FACT: ServiceManager contains a lot of different constants, including: • GRAVITY_DEATH_STAR_I (3.5303614E-7) • GRAVITY_THE_ISLAND (4.815162) • LIGHT_FULLMOON/NO_MOON/CLOUDY
47. #dfua Device Driver Types: Sensors FUN FACT: ServiceManager contains a lot of different constants, including: • GRAVITY_DEATH_STAR_I (3.5303614E-7) • GRAVITY_THE_ISLAND (4.815162) • LIGHT_FULLMOON/NO_MOON/CLOUDY
48. #dfua Device Driver Types • GPS • HID (Human Interface Devices) • Sensors • Audio
49. #dfua Device Driver Types Using audio drivers, your apps can register new audio input/output devices
50. #dfua Device Driver Types public class PlaybackDriver extends AudioOutputDriver { @Override public void onStandbyChanged(boolean inStandby) { ... } @Override public int write(ByteBuffer buffer, int count) { ... } }
51. #dfua Device Driver Types public class PlaybackDriver extends AudioOutputDriver { @Override public void onStandbyChanged(boolean inStandby) { ... } @Override public int write(ByteBuffer buffer, int count) { ... } }
52. #dfua Device Driver Types public class PlaybackDriver extends AudioOutputDriver { @Override public void onStandbyChanged(boolean inStandby) { ... } @Override public int write(ByteBuffer buffer, int count) { ... } }
53. #dfua Connectivity | Peripheral I/O • General Purpose Input/Output (GPIO) • Pulse Width Modulation (PWM) • Serial Communication (I2C/SPI/UART)
54. #dfua Connectivity | Peripheral I/O • General Purpose Input/Output (GPIO) • Pulse Width Modulation (PWM) • Serial Communication (I2C/SPI/UART)
55. #dfua GPIO GPIO pins provide a programmable interface to read the state of a binary input device or control the on/off state of a binary output device.
56. #dfua GPIO ... private Gpio mGpio; @Override protected void onCreate(Bundle savedInstanceState) { ... PeripheralManagerService manager = new PeripheralManagerService(); mGpio = manager.openGpio(GPIO_NAME); ... }
57. #dfua GPIO @Override protected void onDestroy() { ... if (mGpio != null) { mGpio.close(); mGpio = null; } ... }
58. #dfua GPIO ... // Initialize the pin as a high output gpio.setDirection(Gpio.DIRECTION_OUT_INITIALLY_HIGH); // Low voltage is considered active gpio.setActiveType(Gpio.ACTIVE_LOW); ... // Toggle the value to be LOW gpio.setValue(true); ...
59. #dfua GPIO ... // Initialize the pin as a high output gpio.setDirection(Gpio.DIRECTION_OUT_INITIALLY_HIGH); // Low voltage is considered active gpio.setActiveType(Gpio.ACTIVE_LOW); ... // Toggle the value to be LOW gpio.setValue(true); ...
60. #dfua Connectivity | Peripheral I/O • General Purpose Input/Output (GPIO) • Pulse Width Modulation (PWM) • Serial Communication (I2C/SPI/UART)
61. #dfua PWM PWM is a common method used to apply a proportional control signal to an external device using a digital output pin.
62. #dfua PWM • The frequency (Hz) - how often the output pulse repeats. • The period is the time each cycle takes. • The duty cycle (%) describes the width of the pulse within that frequency window.
63. #dfua PWM
64. #dfua PWM Duty (50%)
65. #dfua PWM Duty (50%) Period (100ms)
66. #dfua PWM Most PWM hardware has to toggle at least once per cycle, so even duty values of 0% and 100% will have a small transition at the beginning of each cycle.
67. #dfua PWM public void initializePwm(Pwm pwm) throws IOException { pwm.setPwmFrequencyHz(120); pwm.setPwmDutyCycle(25); // Enable the PWM signal pwm.setEnabled(true); }
68. #dfua Connectivity | Peripheral I/O • General Purpose Input/Output (GPIO) • Pulse Width Modulation (PWM) • Serial Communication (I2C/SPI/UART)
69. #dfua Serial Communication The Inter-Integrated Circuit (IIC or I2C) bus connects simple peripheral devices with small data payloads (e.g. sensors).
70. #dfua Serial Communication Serial Peripheral Interface (SPI) devices are typically found where fast data transfer rates are required (e.g. Graphical displays)
71. #dfua Serial Communication Complex peripheral devices such as GPS modules, LCD displays, and XBee radios typically use Universal Asynchronous Receiver Transmitter (UART) ports (often simply called serial ports) to communicate.
72. #dfua Advanced stuff: Cloud Cloud IoT Core is a fully managed service that allows you to easily and securely connect, manage, and ingest data from millions of globally dispersed devices
73. #dfua Cloud: How to manage a device fleet
74. #dfua Cloud • device manager • protocol bridge
75. #dfua Device Manager Allows individual devices to be configured and managed securely in a coarse-grained way
76. #dfua Protocol bridge The protocol bridge provides connection endpoints for protocols with automatic load balancing for all device connections
77. #dfua Protocol bridge The protocol bridge has native support for secure connection over industry standard protocols such as MQTT, HTTP
78. #dfua Protocol bridge The protocol bridge publishes all device telemetry to Cloud Pub/Sub, which can then be consumed by downstream analytic systems.
79. #dfua Cloud: Other features • End-to-end security • Single global system • Out-of-box data insights
80. #dfua Cloud: Other features • Fully managed and scalable • Role-level access control • Device deployment at scale
81. #dfua Cloud: Other features • Fully managed and scalable • Role-level access control • Device deployment at scale
82. #dfua Worth to mention
83. #dfua Worth to mention Notifications are not supported. Avoid calling the NotificationManager APIs in your apps. (Because there is no status bar)
84. #dfua Worth to mention Dangerous permissions are granted on the next device reboot and do not require run time checks
85. #dfua Worth to mention RenderScript - works, but no one knows how
86. #dfua Worth to mention Multiply applications - yes, but only one with default activity
87. #dfua Worth to mention Forget about “good citizen”. Be a dictator.
88. #dfua Worth to mention Communicating with peripheral hardware introduces blocking operations into the flow of your app.
89. #dfua Worth to mention Use User-space Drivers in separated apps with Foreground Services
90. #dfua Worth to mention No ANR anymore! You can do computation on a Main Thread (but probably you shouldn’t)
91. #dfua Worth to mention FireBase is with us. But don’t forget about latency
92. #dfua Worth to mention • Tensorflow • Google assistant • Smart home integration
93. #dfua Summary • Good for quick prototyping • Java/Kotlin > C/C++ • Still not production ready • Much fun • So experience
94. Thank you! Questions? Vitaliy Zasadnyy Content Manager @ DFUA