Android Things Linux Day 2017

Stefano Sanna(with Giovanni Di Gialluca)

Timeline

2008

2011

2014

2015

2016

Mr Sulu, our coordinates, please...

Physical World Cloud

At a glance

SAFETY & SECURITYSAFETY & SECURITY

HOME APPLIANCES

HOME APPLIANCES

CONNECTED CARS

CONNECTED CARSSMART METERSSMART METERS

INDUSTRY 4.0INDUSTRY 4.0

SALES & VENDINGSALES & VENDING

PORTABILITYPORTABILITY

LARGE, VIBRANT, PROFESSIONAL

COMMUNITY

LARGE, VIBRANT, PROFESSIONAL

COMMUNITY

FULL-STACK CLOUD

SERVICES

FULL-STACK CLOUD

SERVICESSECURITYSECURITY

ON DEVICE INTELLIGENCE

ON DEVICE INTELLIGENCE

MODERN ARCHITECTURE

AND LANGUAGES

MODERN ARCHITECTURE

AND LANGUAGES

Environment● Same architecture

● Same IDE (Android Studio)

● Same programming language(s)

● Same framework

● Same app (Activity) lifecycle

● Same UI widgets (UI?)

● Same application packaging

● Same reliable security for apps and frmware upgrade

● Same passionate community

Feel at home...

… more or less! Where is the UI?

Where is the UI?

Android Things vs Android: in & out

CastDriveFirebase AnalyticsFirebase Cloud MessagingFirebase Realtime DatabaseFirebase Remote ConfigFirebase StorageFitInstance IDLocationNearbyPlacesMobile Vision

CastDriveFirebase AnalyticsFirebase Cloud MessagingFirebase Realtime DatabaseFirebase Remote ConfigFirebase StorageFitInstance IDLocationNearbyPlacesMobile Vision

CalendarContract

ContactsContract

DocumentsContract

DownloadManager

MediaStore

Settings

Telephony

UserDictionary

VoicemailContract

AdMob

Android Pay

Firebase App Indexing

Firebase Authentication

Firebase Dynamic Links

Firebase Invites

Firebase Notifications

Maps

Play Games

Search

Sign-In

CalendarContract

ContactsContract

DocumentsContract

DownloadManager

MediaStore

Settings

Telephony

UserDictionary

VoicemailContract

AdMob

Android Pay

Firebase App Indexing

Firebase Authentication

Firebase Dynamic Links

Firebase Invites

Firebase Notifications

Maps

Play Games

Search

Sign-In

SOM

SOM: System On ModuleA system on a module (SOM) is a board-level circuit that integrates a system function in a single module.

A typical SOM consists of:

● a microcontroller, microprocessor or digital signal processor (DSP)

● memory blocks including a selection of ROM, RAM, EEPROM and/or fash memory

● timing sources

● industry standards interface such as USB, FireWire, Ethernet, UART, SPI

● peripherals including counter-timers, real-time timers and power-on reset generators

● analog interfaces including ADCs and DACs

● voltage regulators and power management circuits

https://en.wikipedia.org/wiki/System_on_module

From prototype...

SYSTEM ON MODULE (SOM) WITH

OS AND APPS


OS AND APPS

BASEBOARD FOR

PROTOTYPING

BASEBOARD FOR

PROTOTYPING

… to production


OS AND APPS


OS AND APPS

STACK OF DEDICATED

BOARDS

STACK OF DEDICATED

BOARDS

Setup the development environment● Android Studio 3.0

– Android 7.0 support for Developer Preview 4– Android 8.0 support for Developer Preview 5

upwards● Google Account

– Access to Android Things Console● Hardware

– SOM – Development Kit– Sensor, actuators, interfaces

Boards

Intel Edison Intel Joule NXP Pico i.MX6UL Raspberry Pi3

PRICE $55 > $200 $70 $22

SDK PRICE

$150 > $300 - $22

CPU Atom DC @500Mhz Atom QC @1.5GHz NXP i.MX6Ultralite ARM Cortex A7 @500MHz

Broadcom BCM2837QC @1.2GHz Cortex

A53

RAM 1GB 3-4GB 512MB 1GB

STORAGE

4GB 8-16GB 4GB microSD

DISPLAY

NO HDMI NO HDMI

CAMERA

NO CSI-2 NO CSI-2

AUDIO USB 2.0 USB 2.0 3.5mm Analog USB 2.0 & 3.5mm Analog

NET WiFi n, BT 4.0 WiFi ac, BT 4.2 Ethernet, WiFi n, BT 4.1 GB Ethernet, WiFi n, BT 4.1

USB USB 2.0 OTG 2x USB 2.0 HOST + USB 3.0 OTG

USB 2.0 HOST + USB 2.0 OTG

4x USB 2.0 HOST

GPIO 2x UART, 2x I2C,SPI 2ch, 14 GPIO

4x UART, 5x I2C, 2x SPI, up to 48 GPIO

8x UART, 4x I2C, 4x SPI, > 20 GPIO

2x UART, 2x I2C, 2x SPI, up to 26 GPIO

Select a board ● Intel Edison

– Damn small!– No UI, no Ethernet– ADB via USB– Obsolete (will not receive upgrades), but easily

sold on eBay at afordable price● Raspberry Pi3

– Damn cheap!– Ethernet + WiFi– HDMI + Camera + lot of – extension boards: AI+VR+IoT!– Diferent confgs can be tested swapping the SD

Deployment and update

APPby Developer

APPby Developer

OSby Google

OSby Google

DEVELOPER UPDATE

CONSOLE

DEVELOPER UPDATE

CONSOLE

DeviceDeviceOTA

Console [DEMO]

Bundle

Android Things vs Android● No UI == some hacking

– ADB via USB is not available on any board: it must be confgured over network

– Wireless Network must be confgured using ADB. See previous item: loop!

– Bluetooth and other stuf must be managed programatically

● Power management must be implemented from scratch

● RTC could not be available: without time synhcronization certifcate validation may fail

Hello World!

System.out.println(“Hello World!”);

Hello World! [DEMO]

Hello World!

PeripheralManagerService pms = new PeripheralManagerService();

Gpio LED = pms.openGpio("IO13");

LED.setDirection(Gpio.DIRECTION_OUT_INITIALLY_LOW);

LED.setValue(true);

API Extensions

● General Purpose Input/Output (GPIO)

● Pulse Width Modulation (PWM)

● Analog Input

● I2C

● UART

● SPI

Warning● Moving from software to hardware playground

requires some skills and attention

● Boards may accept 3.3v or 5v peripherals or both: check voltage matching before connecting devices otherwise you may damage the hardware

● Flying cables, jumpers, breadboards and misc tools may cause a short circuit in milliseconds and fre your beloved workstation

● Boards with eMMC may be “bricked” if bootloader update fails. It is strongly recommended to move early steps on a board with removable storage (Raspberry Pi3)

General Purpose Input/Output (GPIO)● Digital I/O with two logical states (true/false)

mapped on two electrical states (high/low)


List<String> portList = pms.getGpioList();

mGpio = pms.openGpio(portList.get(0));

mGpio.setValue(true | false); // write

boolean state = mGpio.getValue(); // read

General Purpose Input/Output (GPIO)GpioCallback mGpioCallback = new GpioCallback() {

@Override

public boolean onGpioEdge(Gpio gpio) {

mDevice.getValue(); // Read the active low pin state

return true; // Continue listening for more interrupts

}

@Override

public void onGpioError(Gpio gpio, int error) { }

};

// EDGE_BOTH |EDGE_NONE | EDGE_RISING | EDGE_FALLING

mGpio.setEdgeTriggerType(EDGE_BOTH);

mGpio.registerGpioCallback(mGpioCallback);

GPIO for analog input● Android Things API currently does not support

analog input (think about “analogRead()” provided by Arduino)

● An Analog To Digital Converter (ADC) must be used to read voltage level

● The 2-channel converter ADC0832 can be easily used to solve this issue

Start communication

Analog input

Clock

Output

Channelselection

Writing the ADC0832 driver [1]

// configuring GPIO connections

gpioD0.setDirection(Gpio.DIRECTION_IN);

gpioD1.setDirection(Gpio.DIRECTION_OUT_INITIALLY_HIGH);

gpioCLK.setDirection(Gpio.DIRECTION_OUT_INITIALLY_HIGH);

gpioCS.setDirection(Gpio.DIRECTION_OUT_INITIALLY_HIGH);


// selecting channel 1

for (int i = 0; i < 3; i++) { // Input MUX address

if (i == 0 || i == 1 || ch == 1) { gpioD1.setValue(true); }

else { gpioD1.setValue(false); }

gpioCLK.setValue(true); //Clock signal

gpioCLK.setValue(false);

}


for (int i = 0; i < 8; i++) { // Read 8 bits from ADC

gpioCLK.setValue(true); //Clock signal

gpioCLK.setValue(false);

ad = ad << 1;

boolean value = gpioD0.getValue();

if (value) {

ad |= 0x01;

}

}

Writing a driver FAQ● Is this always so complicated?

– YES● Could it be simplifed?

– YES● How???

– Using a driver library :-)● Where?

– Android Things user-space drivers (by Google)– Useful Packages and Modules (UPM) and MRAA

(by Intel)

Pulse Width Modulation (PWM)● Uses a square wave signal (with assigned

frequency and duty-cycle) to control devices such as servo motors.

Pulse Width Modulation (PWM)● Values for this servo:

– 50HZ , 7.5% -> Neutral position(90°)– 50HZ , 3.75% -> Min position (0°)– 50HZ , 11.25% -> Max position (180°)


List<String> portList = pms.getPwmList(); //List of all PWM ports

Pwm mPwm = pms.openPwm(portList.get(0));

mPwm.setPwmFrequencyHz(50);

mPwm.setPwmDutyCycle(7.5);

mPwm.setEnabled(true); //start pulsing

Serial Communication: I2C, UART, SPI


List<String> mI2Cs = pms.getI2cBusList();

List<String> mUARTs = pms.getUartDeviceList();

List<String> mSPIs = pms.getSpiBusList();

Inter-Integrated Circuit (I2C)● Synchronous, fxed clock speed, half-duplex,

master-slave (SW), low boundrate

● Peripheral specs: addresses for all connected slave, addresses for all information, MSB only

● Connection:

– Shared clock signal (SCL), Shared data line (SDA)– Common ground reference (GND)


I2cDevice mI2C = pms.openI2cDevice(I2C_DEVICE_NAME, I2C_ADDRESS);

byte[] data = new byte[3];

mI2C.readRegBuffer(startAddress, data, data.length);

mI2C.writeRegBuffer (startAddress, data, data.length)

Typical I2C devices [DEMO]

Universal Asynchronous Receiver Transmitter (UART)

● Every time you see the TX-RX pair, there’s a UART available!

● The simplest serial port used for expansion boards or even home appliances (often for logging)

● Features: point to point, asynchronous (no clock), full duplex

● Peripheral specs: boudrate, parity bit, data size, stop bit

● Physical Interface: 3 basic wires TX, RX, GND + 2 optional wires: request to send (RTS) and clear to send (CTS)

UART: setupPeripheralManagerService pms = new PeripheralManagerService();

UartDevice uart = pms.openUartDevice(UART_DEVICE_NAME);

mUart.setBaudrate(115200);

// 8N1

mUart.setDataSize(8);

mUart.setParity(UartDevice.PARITY_NONE);

mUart.setStopBits(1);

//enable/disable HW flow control

mUart.setHardwareFlowControl

(UartDevice.HW_FLOW_CONTROL_AUTO_RTSCTS);

mUart.setHardwareFlowControl(UartDevice.HW_FLOW_CONTROL_NONE);

UART: read/writemUart.write(buffer, buffer.length); mUart.read(buffer, buffer.length));

mUart.registerUartDeviceCallback(new UartDeviceCallback() {

public boolean onUartDeviceDataAvailable(UartDevice uart) {

byte[] buffer = new byte[20];

int count;

try {

while ((count = uart.read(buffer, buffer.length)) > 0) {

Log.d("TAG", "Read " + count + " bytes from peripheral");

}

} catch (IOException e) { Log.d("TAG", "Unable to access UART device");}

return true; // Continue listening for more interrupts

}

public void onUartDeviceError(UartDevice uart, int error) { }

});

RFID Reader [DEMO]

+

NFC badge reader [1/3 DEMO]private void readNFC() {

try {

FirebaseDatabase database = FirebaseDatabase.getInstance();

DatabaseReference myRef = database.getReference("presenze");


UartDevice uart = pms.openUartDevice("UART1");

uart.setBaudrate(19200); uart.setDataSize(8);

uart.setParity(UartDevice.PARITY_NONE); uart.setStopBits(1);

byte[] readCMD = new byte[]{(byte) 0xAA, (byte) 0xBB, 0x02, 0x20, 0x22};

// prefix + 2 bytes

byte[] noTAG_PREFX = new byte[]{(byte) 0xAA, (byte) 0xBB, (byte) 0x02};

// prefix + 1 byte to skip + 4 bytes ID + 1 byte end

byte[] foundTAG_PREFX = new byte[]{(byte) 0xAA, (byte) 0xBB, (byte) 0x06};

NFC badge reader [2/3 DEMO] byte[] prefix = new byte[3]; byte[] buffer = new byte[6];

byte[] data = new byte[4]; byte[] lastRead = new byte[4];

while (true) {

uart.write(readCMD, 5);

uart.read(prefix, 3);

if (Arrays.equals(prefix, noTAG_PREFX)) {

uart.read(buffer, 2);

} else if (Arrays.equals(prefix, foundTAG_PREFX)) {

uart.read(buffer, 1); // skip 20

uart.read(data, 4);

if (!Arrays.equals(data, lastRead)) {

myRef.child(Long.toString(System.currentTimeMillis())).setValue(Arrays.toString(data));

lastRead = Arrays.copyOf(data, 4);

}

uart.read(buffer, 1); // skip 0D

}

}

NFC badge reader [3/3 DEMO]

} catch (Exception e) { e.printStackTrace(); }

}

private void d(String message) { Log.d("LD17", message); }

}

Serial Peripheral Interface (SPI)● Full duplex, synchronous, master-slave (HW)

● Params: Frequency, BPW, MSB/LSB, CLOCK mode

● Connection:

● 2 Bus lines

● Master Out Slave In (MOSI)

● Master In Slave Out (MISO)

● Clock [CLK]

● Slave selection pin [CS or SS]

● Fastest serial connection available: best to communicate with slave boards that have full (and low level) control of all sensor and actuators

SPIPeripheralManagerService pms = new PeripheralManagerService();

mSpi = pms.openSpiDevice(SPI_DEVICE_NAME);

mSpi.setMode(SpiDevice.MODE0); // MODE0 | MODE1 | MODE2 | MODE3

mSpi.setFrequency(500000); // 500 KHz

mSpi.setBitsPerWord(8); // 8 BPW

mSpi.setBitJustification(false); // MSB first

// Write & read

mSpi.write(buffer, buffer.length);

byte[] response = new byte[32];

mSpi.read(response, response.length);

48

DEXTER BrickPi● Raspberry Pi3 extension module that provides:

– 4 Mindstorms NXT/EV3 Motor ports– 4 Mindstorms NXT/EV3 Sensor ports– Extra I2C sensor bus– SPI interface to Raspberry Pi3– Uniform request/response binary protocol– Seamless power management (internal,

external, both)

Never forget to read the release notes!

Never forget to read the release notes!List<String> portList = mManager.getGpioList();

for (String gpioName: portList) {

Gpio gpio;

if (gpioName.equals("BCM4") ||

gpioName.equals("BCM5") ||

gpioName.equals("BCM6")) {

gpio = mManager.openGpio(gpioName);

gpio.setDirection(Gpio.DIRECTION_OUT_INITIALLY_LOW);

gpio.setActiveType(Gpio.ACTIVE_HIGH);

gpio.setValue(false);

gpio.close();

}

}

51

BrickPi & LEGO Rover (video)

52

Conclusion● Android Things brings the power and richness of

Android Platform to the IoT World

● Secure, portable, scalable, ready-for-the-cloud, ready-for-independence :-)

● Upcoming board with cellular network connectivity and near-to-wearable devices will open the doors to new classes of applications and services

53

Speaker● Co-founder GULCh (21 years ago…)

● Manager @ Open Reply

● Technical writer

● Linux User since 1994

● Android Developer since 2009

● Billionaire (still to come)

● Reference

– Twitter: @gerdavax– http://www.gerdavax.it – gerdavax presso la posta di Big G

54

Copyright and disclaimer● This presentation has been written by Stefano

Sanna and Giovanni Di Gialluca. It has been derived from “Android Things in action”, presented at Droidcon 2017 in Turin.

● This presentation is published under the Creative Commons License “Attribution-NonCommercial-ShareAlike 4.0 International”

● All brands, trademarks and technologies mentioned in this presentation are properties of respective owners and they have been used just for educational purpose.

Android Things Linux Day 2017

Devices & Hardware