Using Android Things
to Detect &
Exterminate
Reptilians

Android is
EVERYWHERE (01)
(01)
Reptilians too are everywhere, but they suck.

Android Things

"If you can build an
app, you can build a
device!"

8-bit Distributed Piano (02)
(02)
https://riggaroo.co.za/android-things-building-distributed-piano/

Play Music Like a Scientist

Beer Can Music Player (03)
(03)
http://nilhcem.com/android-things/discovering-the-I2C-api-creating-a-capacitive-sensor-driver

Notification Cat (04)
(04)
http://nilhcem.com/android-things/bluetooth-low-energy

Google Assistant powered Robot
(05)
(05)
http://nilhcem.com/android-things/create-your-google-assistant-robots

OK, BUT, WHY?
I mean... I can use an Arduino too

Perfect for
• Doing some computation locally
• Using Google Services
• A secure platform
• Prototype and production

Perfect for
• Doing some computation locally
• Using Google Services
• A secure platform
• Prototype and production

Perfect for
• Doing some computation locally
• Using Google Services
• A secure platform
• Prototype and production

Perfect for
• Doing some computation locally
• Using Google Services
• A secure platform
• Prototype and production

Compatible boards (06)
• Raspberry Pi 3
• NXP i.MX7D/i.MX6UL
• Intel Edison/Joule (discontinued)
(06)
https://developer.android.com/things/hardware/developer-kits.html

Raspberry Pi 3 - NXP i.MX7D

SOM (System on module)

SOM (System on module)

Edison Candle (07)
(07)
https://github.com/androidthings/edison-candle

SOMs are pre-certified for
regulator approvals

Perfect for
• Doing some computation locally
• Using Google Services
• A secure platform
• Prototype and production

Facts
• Humans don't use their brain to its full capacity
• Humans are distracted by media, entertainment, and
politics.
• Borders, country lines lead to endless wars and conflicts

Reason?

REPTILIANS

Reptilian conspiracy theory (08)
(08)
https://www.theatlantic.com/national/archive/2013/04/12-million-americans-believe-lizard-people-run-our-country/
316706/

Reptilian
• Altered our DNA so we don't fully use our brain
• Control humans with media / politics
• Have, through the generations, ruled the world

Using Android Things
to Detect &
Exterminate
Reptilians

Detect

TensorFlow (09)
(09)
http://nilhcem.com/android/custom-tensorflow-classifier

TensorFlow codelabs
• TensorFlow for Poets (10)
• TensorFlow for Poets 2: Optimize for Mobile (11)
• Android Things Image Classifier (12)
(12)
https://codelabs.developers.google.com/codelabs/androidthings-classifier/index.html
(11)
https://codelabs.developers.google.com/codelabs/tensorflow-for-poets-2/
(10)
https://codelabs.developers.google.com/codelabs/tensorflow-for-poets/

Inception v3
• Deep learning model for image recognition
• Transfer learning

Gather lots of images

Transfer learning
python tensorflow/examples/image_retraining/retrain.py
--bottleneck_dir=~/tf_files/bottlenecks
--how_many_training_steps 4000
--model_dir=~/tf_files/inception
--output_graph=~/tf_files/retrained_graph.pb
--output_labels=~/tf_files/retrained_labels.txt
--image_dir ~/tf_files/reptilians

Generated files
• retrained_graph.pb
• retrained_labels.txt

Generated files
$ cat retrained_labels.txt
human
reptile
reptilian

Mobile model optimizations
python tensorflow/python/tools/optimize_for_inference.py
--input=~/tf_files/retrained_graph.pb
--output=~/tf_files/optimized_graph.pb
--input_names="Mul"
--output_names="final_result"

TensorFlow Android Classify
sample (13)
(13)
https://github.com/tensorflow/tensorflow/tree/master/tensorflow/examples/android

TensorFlow Inference
val inferenceInterface = TensorFlowInferenceInterface(getAssets(), MODEL_FILE)
val labels = loadLabels() // [ "reptilian", "reptile", "human" ]
fun doRecognize(image: Bitmap) {
val pixels = image.toPixelsArray()
inferenceInterface.feed(INPUT_NODE, pixels, NETWORK_STRUCTURE)
inferenceInterface.run(arrayOf(OUTPUT_NODE))
val outputs = FloatArray(labels.size)
inferenceInterface.fetch(OUTPUT_NODE, outputs)
}

TensorFlow Inference
labels = [ "reptilian", "reptile", "human" ]
outputs = [ 0.0098f , 0.0039f , 0.9863f ]

Test data

AndroidManifest.xml
<application>
<uses-library android:name="com.google.android.things" />
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<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>
</application>

MainActivity
class MainActivity : Activity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
}
}

"Hi! I use RelativeLayouts, lol"

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:src="@drawable/background"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<ImageView
android:src="@drawable/reptilian"
android:layout_width="280dp"
android:layout_height="224dp"
android:layout_gravity="bottom|center_horizontal" />
</FrameLayout>

"Layouts are dusty"

build.gradle
dependencies {
compileOnly 'com.google.android.things:androidthings:0.5.1-devpreview'
}

Peripheral I/O APIs

Arduino Starter Kit

Peripheral I/O APIs (14)
• GPIO
• PWM
• I²C
• I²S
• SPI
• UART
(14)
https://developer.android.com/things/sdk/pio/index.html

Blinking LEDs

val pioService = PeripheralManagerService()
val ledGpio = pioService.openGpio("BCM4")

Magic happens here
ledGpio.value = true
Thread.sleep(1000)
ledGpio.value = false

LEDs (15)
(15)
https://fullmoonwanderer.deviantart.com/art/Reptilian-LED-resin-eyes-552330846

PeripheralManagerService
fun openGpio(…): Gpio
fun openPwm(…): Pwm
fun openSpiDevice(…): SpiDevice
fun openUartDevice(…): UartDevice
fun openI2cDevice(…): I2cDevice
fun openI2sDevice(…): I2sDevice

fun writeBuffer(device: I2cDevice, data: ByteArray) {
device.write(data, data.size)
}

Drivers are standard
Android libraries (16)
(17)
(17)
https://github.com/amitshekhariitbhu/awesome-android-things
(16)
https://github.com/androidthings/contrib-drivers

build.gradle
compile 'com.google.android.things.contrib:driver-ssd1306:0.4'

MainActivity.kt
val display = Ssd1306("I2C1")
display.setPixel(x = 0, y = 0, on = true)

val display = Ssd1306("I2C1")
val bmp = BitmapFactory.decodeResource(resources, R.drawable.background)
BitmapHelper.setBmpData(display, 0, 0, bmp, false)
display.show()

Android Things
TensorFlow Sample
(18)
(18)
https://github.com/androidthings/sample-tensorflow-imageclassifier

Camera

Cucumbers (?!?) (19)
(19)
https://cloud.google.com/blog/big-data/2016/08/how-a-japanese-cucumber-farmer-is-using-deep-learning-and-
tensorflow

Detect when
someone is
approaching

Ultrasonic Sensor (HC-SR04)

Ultrasonic Sensor
(HC-SR04)
1. Trigger
2. Echo

No Android Things
compatible drivers

Arduino to the rescue

Arduino to the rescue

Arduino to the rescue
void loop() {
distance = getDistanceInCentimeters();
Serial.println(distance);
delay(1000);
}

Arduino to the rescue

Read data from USB (20)
Hcsr04LiveData(this)
.observe({lifecycle}) { distanceInCm ->
Log.i(TAG, "Distance (cm): $distanceInCm")
}
(20)
https://github.com/Nilhcem/usbfun-androidthings

HC-SR04
Hcsr04LiveData(this)
.observe({lifecycle}) { distanceInCm ->
if (distanceInCm < 25) {
takePicture()
}
}

git commit -m "Kill reptilian when detected"
if (detected.isReptilian()) {
exterminate()
}

Exterminate

Option #1: Gun

Servo motor

Servo motor

Servo motor

PWM servo
compile 'com.google.android.things.contrib:driver-pwmservo:0.3'

Moving the servo
val servo = Servo("PWM0")
servo.setAngleRange(0.0, 180.0)
servo.setPulseDurationRange(1.0, 2.0)
servo.enable = true
servo.angle = servo.minimumAngle

Moving the servo
servo.angle = 42.0

Option #2:
Flamethrower

Flamethrower (21)
(21)
https://www.youtube.com/watch?v=fh6oJZZ27Ro

Remote control
• Nearby Connections API
• Bluetooth LE
• Embedded http server
• Whatever you want

Option #3: Chainsaw

Relay module (22)
(22)
http://nilhcem.com/android-things/google-assistant-smart-home

Magic happens here
relay.value = true

val colorAnimator = ValueAnimator.ofFloat(0f, 360f).apply {
duration = 8000
repeatCount = ValueAnimator.INFINITE
repeatMode = ValueAnimator.REVERSE
addUpdateListener { animator ->
val leds = getLedsColors(animator.animatedValue)
ledstrip.write(leds)
}
start()
}

val path = Path().apply {
moveTo(0f, 0f)
lineTo(0.001f, 400f / 2000f) // 0 secs -> 2.5 fps
lineTo(3f / 23f, 400f / 2000f) // 3 secs -> 2.5 fps
lineTo(6f / 23f, 20f / 2000f) // 6 secs -> 50.0 fps
lineTo(18f / 23f, 20f / 2000f) // 18 secs -> 50.0 fps
lineTo(1f, 1f) // 23 secs -> 0.5 fps
}
val frameDelayAnimator = ValueAnimator.ofInt(0, 2000).apply {
duration = 23000
repeatCount = 0
interpolator = PathInterpolator(path)
start()
}

Using Android Things
to Detect &
Exterminate
Reptilians

Conclusion

Android Things is Fun

Easy to get started

Reptilians suck (23)
(23)
Unless Reptilians are just an analogy to tell you not to blindly trust media and get you think about reality in a different way

Be a maker
Try Android Things, really

Using Android Things to
Detect & Exterminate Reptilians
• Twitter:
@Nilhcem
• Slides:
bit.ly/reptilethings