Build your first Android

Things application

Keval Patel

Android Developer @

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Agenda

- Introduction to Raspberry Pi.

- Specifications & Schematics of Raspberry Pi.

- How to connect Raspberry Pi to your computer?- Create a new project for Android Things.

- What’s different than normal app development?

- Accessing hardware components in Android app.

- Introduction: Smart Switch App

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What is Raspberry Pi?

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What is Raspberry Pi?

A computer.

A small single-board computer that plugs into your TV and a keyboard,

which can be used for many of the things that your average desktop does -

spreadsheets, word-processing, games and it also plays high-definition video.

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What is Raspberry Pi?

Small - Size of the credit card.

Affordable - Just $35!!!

Single Board SoC.

Consumes less than 5W power.

Developed by Raspberry Pi foundation.

Board for the hobbyist.

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Which OS you can run?

- Raspbian OS

- Fedora OS

- Debian OS

- Windows 10

- And now Android...

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Raspberry Pi 3 Model B

- Released in Feb 2016.

- Costs $35.

- Supports Android Things.

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Raspberry Pi 3 Model B Specification

- Quad-core 64-bit ARM Cortex-A53, 1.2GHz

- Broadcom VideoCore IV

- 1GB LPDDR2 (900 MHz)

- 10/100 Ethernet

- 2.4GHz 802.11n wireless

- Bluetooth 4.1 and Bluetooth Low Energy

- 40-pin GPIO header

- Ports: HDMI, 3.5mm analog audio-video jack, 4× USB 2.0, Ethernet, Camera

Serial Interface (CSI), Display Serial Interface (DSI) 9

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GPIO

- GPIO = General Purpose Input Output.

- You can configure that pin to act as

input or output pin at runtime.

- No predefined purpose, and go unused

by default.

- Raspberry Pi has 40 GPIO pins.

- The pins allow us to interact with

different components and receive and

send information to them. 11

GPIO Pin Diagram

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How to connect with Raspberry Pi?

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How to connect with Raspberry Pi?

1. Connect USB cable for power.

2. Connect an Ethernet cable your local network.

3. Connect an HDMI cable to an display. (Optional)

4. Find the IP of Raspberry Pi using IP scanner tool. (e.g.

Angry IP scanner.) The host name will be “Android.local”.

5. Connect to this IP address using the adb.

$ adb connect <ip-address>

connected to <ip-address>:5555

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How to connect with Wi-Fi?

1. Send an intent to the Wi-Fi service with the SSID and passcode of your Wi-Fi

network. You need to do it only when connecting to new Wi-Fi network.

$ adb shell am startservice \

-n com.google.wifisetup/.WifiSetupService \

-a WifiSetupService.Connect \

-e ssid <Network_SSID> \

-e passphrase <Network_Passcode>

$ adb connect <ip-address>

connected to <ip-address>:5555

2. Find the IP of Raspberry Pi using IP scanner tool.

3. Connect to this IP address using the adb.

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How to check if the internet access available?

rpi3:/ $ ping google.com

PING google.com (216.58.199.142) 56(84) bytes of data.

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Creating

Android Things

Project In

Android Studio

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Build Android Things Project

- Create new android project.

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Build Android Things Project

- Set the minSdkVersion for the project to 24.

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Build Android Things Project

- Add “com.google.android.things” library to “AndroidManifest.xml”.

<application

android:allowBackup="true"

android:icon="@mipmap/ic_launcher"

android:label="@string/app_name"

android:theme="@style/AppTheme">

<uses-library android:name="com.google.android.things"/>

<activity android:name=".MainActivity">

....

....

</activity>

</application>

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Add Home activity support

- "Home activity" in its manifest as the main entry point for the system to

automatically launch on boot.

<activity android:name=".MainActivity">

<intent-filter>

<action android:name="android.intent.action.MAIN"/>

<category android:name="android.intent.category.LAUNCHER"/>

</intent-filter>

<!-- 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>

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Android Things

Vs.

Android Phone

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Android Things App Vs. Phone App

- In Android Things UI is optional.

- Android Things launcher does not

have an app drawer. You need to

launch the application using ADB.

- There is no system-wide status

bar and window shade in Android

Things. So, notifications are not

supported.

- No system-wide navigation bar.

So, back button, home button, and

app switcher are supported. 23

Android Things App Vs. Phone App

- Android Things supports a subset of the Google APIs for Android.

- Each release of Android Things bundles the latest stable version of Google

Play Services, and requires at least version 10.0.0 of the client SDK.24

- No runtime permission. Just declare permission in AndroidManifest. (Just like

old days!!!)

- No support for the Google Play.

Android Things App Vs. Phone App

- Doesn't include the all of the standard system apps and content providers.

Like SMS application and SMS provider. Avoid using them.

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How to access GPIO?

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Setting GPIO

- Open GPIO pin using PeripheralManagerService.

PeripheralManagerService service = new PeripheralManagerService();

mRedPin = service.openGpio(BoardDefaults.getGPIOForRedLED());

- Define pin as input or output.

//Define as output

mRedPin.setDirection(Gpio.DIRECTION_OUT_INITIALLY_LOW);

//Or

mRedPin.setDirection(Gpio.DIRECTION_OUT_INITIALLY_HIGH);

//Set as input

mRedPin.setDirection(Gpio.DIRECTION_IN);

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Peripheral Driver Library

- There are many sensors we may need in our project.

- All sensors have different specs and different types of

input/output.

- You don’t want to write code to integrate those sensors

in your application.

- Peripheral Driver Library contains pre-written user

drivers for popular peripherals available for supported

Android Things hardware.

- It is open sourced.

(https://github.com/androidthings/contrib-drivers) 28

Let’s build something REAL!!!

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Smart Switch

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Control the devices like fan, light bulb using your phone.

- Can control 1 fan, 1 light bulb and 1 LED.

- Uses firebase real-time database to sync the

status of the home device between raspberry pi

and companion app.

Components required

- Raspberry Pi

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- 2 x 5V Relay

- 1 LED

- 1K resistor

- Breadboard

- Wires/Connectors

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Firebase Real Time

Database

It’s demo time!!!

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What’s next???

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- Go ahead and download from GitHub (https://goo.gl/1CHzrB). Play with your

own devices.

- Try out different samples from Android Things samples

(https://goo.gl/aTRWTN) page.

- Make your own project.

References

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- Android Things - Android Developers (https://goo.gl/PefyPY)

- Android Things - GitHub (https://goo.gl/AWA1Co)

- Android Things – Hardware Basics for the Software Engineer

(https://goo.gl/ini66V)

- SmartSwitch - Github (https://goo.gl/1CHzrB)

What you are going to build

now?

@kevalpatel2106

@multidots

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