IotCeption
Energy Measurement of Android Things
on Raspberry PI 3 with Arduino Uno
[Olivier Philippot - @simplygreenit]

Who I am?
CTO Greenspector
@simplygreenit

Why you need to measure energy ?

In Classical Android
import android.os.BatteryManager;
import android.content.Context;
BatteryManager mBatteryManager =
(BatteryManager)Context.getSystemService(Context.BATTERY_SERVICE);
Long energy =
mBatteryManager.getLongProperty(BatteryManager.BATTERY_PROPERTY_ENERGY_COUNTER);
Slog.i(TAG, "Remaining energy = " + energy + "nWh");

Energy ...

The project schema ...
Shunt : INA219

I2C Interface

In real life

Android Things

The project under test
1 Raspberry Pi 3
1 Screen + 1 HDMI (Optional)
1 Ethernet
1 USB Cable for power (With some modifications)
1 micro SDCard
1 Rainbow Hat project

Why so much hate?
I2C can be read on Android Things ?

Arduino to measure
Arduino IDE + INA219 Library (C)
shuntvoltage = ina219.getShuntVoltage_mV();
busvoltage = ina219.getBusVoltage_V();
current_uA = ina219.getCurrent_mA()*1000;
loadvoltage = busvoltage + (shuntvoltage / 1000);
poweruWh = loadvoltage * current_uA;
Serial.println(poweruWh);
delay(100);

Serial reading on PC

Serial reading in golang
In Arduino program :
Serial.begin(115200);
Serial library in Go: github.com/goburrow/serial
flag.StringVar(&address, "a", "/dev/ttyACM0", "address")
flag.IntVar(&baudrate, "b", 115200, "baud rate")
flag.IntVar(&databits, "d", 8, "data bits")
flag.IntVar(&stopbits, "s", 2, "stop bits")
flag.StringVar(&parity, "p", "N", "parity (N/E/O)")

Making an computer oscillo
Highchart which read the data : http://localhost:8000/

Now we can play...

Results

Autonomy ?
1,4w in continuous / 5v = 280mAh
3000mAh battery ~ 11h of autonomy
2w in continuous / 5v = 400mAh
3000mAh battery ~ 7,5h of autonomy

Conclusion : Measure, Measure and
Measure
For Energy questions : @simplygreenit