Sensor Stack in Lollipop: what's new and why you should care about it (Droidcon Torino 2015)

Sensor Stack in Lollipop: what's new and

why you should care about itDroidcon Torino 2015

Friday, April 10 speaker: Claudio Capobianco c.capobianco@snapback.io

why we do care about sensors

why we do care about sensors

context awareness

why we do care about sensors

context awareness

improve user interaction

why we do care about sensors

context awareness

improve user interaction

wearable

why we do care about sensors

context awareness

improve user interaction

wearable

internet of things

problem power performances

problem energy consumption

what are the main causes of energy consumption in smartphones?

what are the main causes of energy consumption in smartphones?

peripherals ~33%processor(s) ~28%antennas (network) ~23%display ~16%

source: 2014 Snapback S.r.l.

what are the main causes of energy consumption in smartphones?

peripherals ~33%processor(s) ~28%antennas (network) ~23%display ~16%

source: 2014 Snapback S.r.l.

dive into the problem

batching

my app

onSensorChanged()

my app my app my app

onSensorChanged() onSensorChanged() onSensorChanged()

samplingPeriod

my app

batching: new in KitKat (API 19)

FIFO (HW)

maxReportLatencyonSensorChanged()onSensorChanged()

samplingPeriod

register proximity sensor with batching

SensorManager sensorManager = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE);

Sensor proximitySensor =sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);

sensorManager.registerListener(mListener,proximitySensor,SensorManager.SENSOR_DELAY_NORMAL, maxLatency);

register proximity sensor with batching

SensorManager sensorManager = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE);

Sensor proximitySensor =sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);

sensorManager.registerListener(mListener,proximitySensor,SensorManager.SENSOR_DELAY_NORMAL, maxLatency);

get Sensor Manager

register proximity sensor with batching

SensorManager sensorManager = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE);

Sensor proximitySensor =sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);

sensorManager.registerListener(mListener,proximitySensor,SensorManager.SENSOR_DELAY_NORMAL, maxLatency);get proximity sensor

register proximity sensor with batching

SensorManager sensorManager = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE);

Sensor proximitySensor =sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);

sensorManager.registerListener(mListener,proximitySensor,SensorManager.SENSOR_DELAY_NORMAL, maxLatency);

register the sensor listener

register proximity sensor with batching

SensorManager sensorManager = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE);

Sensor proximitySensor =sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);

sensorManager.registerListener(mListener,proximitySensor,SensorManager.SENSOR_DELAY_NORMAL, maxLatency);

set samplingperiod [μs]

register proximity sensor with batching

SensorManager sensorManager = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE);

Sensor proximitySensor =sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);

sensorManager.registerListener(mListener,proximitySensor,SensorManager.SENSOR_DELAY_NORMAL, maxLatency);

set max report latency [μs]

dive into the problem

batching

wake-up and non-wake-up

what happens when the smartphone is suspended?

what happens when the smartphone is suspended?

wake-upsensor

non-wake-upsensor

wake up the SoC and deliver events

events are lost

which are the wake-up sensors?

up to KitKatmost non-wake-up sensors, except proximity sensor and significant motion detectorcontinuous sensing of other sensor only preventing suspend mode with a wake-lock

which are the wake-up sensors?

up to KitKatmost non-wake-up sensors, except proximity sensor and significant motion detectorcontinuous sensing of other sensor only preventing suspend mode with a wake-lock

starting in Lollipopmost sensors can be defined as both wake-up and non-wake-up variantscontinuous sensing is officially supported

which are the wake-up sensors?

register a wake-up and non-wake-up sensor

Sensor wakeUpAccelerometerSensor =sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER, true);

Sensor nonWakeUpProximitySensor =sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY, false);

Sensor wakeUpProximitySensor =sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY, true);

register a wake-up and non-wake-up sensor

Sensor wakeUpAccelerometerSensor =sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER, true);

Sensor nonWakeUpProximitySensor =sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY, false);

Sensor wakeUpProximitySensor =sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY, true);

boolean wakeUp

register a wake-up and non-wake-up sensor

Sensor wakeUpAccelerometerSensor =sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER, true);

Sensor nonWakeUpProximitySensor =sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY, false);

Sensor wakeUpProximitySensor =sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY, true);

get wake-up accelerometer sensor

(if it exists)

register a wake-up and non-wake-up sensor

Sensor wakeUpAccelerometerSensor =sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER, true);

Sensor nonWakeUpProximitySensor =sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY, false);

Sensor wakeUpProximitySensor =sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY, true); get non-wake-up

proximity sensor(if it exists)

register a wake-up and non-wake-up sensor

Sensor wakeUpAccelerometerSensor =sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER, true);

Sensor nonWakeUpProximitySensor =sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY, false);

Sensor wakeUpProximitySensor =sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY, true);

get wake-up proximity sensor (default)

batching + wake-up sensors

batching + wake-up sensorsenablers of a new generation

of applications

a revolution that involves the full stack

hardwaremanufacturer

Google

AOSPcontributors

applicationdevelopers

Claudio Capobianco c.capobianco@snapback.io

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