1. Android Power Calculations Approaches and Best Practice Hafed Alghamdi

2. Overview Why Android Devices Power Efficiency in Mobile Device Application Development Considerations Power Consumption Measurement Approaches Power Consumption Measurement Best Practice

3. Power Consumption Measurement Approaches Offline Measurement approach External measuring device (Ammeter) It is recommended to measure power with a “fake” test battery Most of the time fake batteries are not good enough to provide robust electrical contact. Online Measurement approach Good technique for applications developers Easy to use inside the code and provide reasonable results

4. Offline Measurement Approach Moonson, Agilent and other Power Monitors Very Expensive Provide accurate results Yoctopuce digital ammeter Open source management software It can store data in a database Regular Ammeter for one simple task at a time

5. Online Measurement Approach PowerTutor developed by University of Michigan (5% fault ) Supports only HTC G1, HTC G2 and Nexus One Android mobile phones Little Eye Aimed to support all Android devices The company was acquired by Facebook and the tool disappeared from the internet Android Power Profiles It can be used directly in your code Approximation with this framework is the most accurate method for collecting power data Trepn™ Plug-in for Eclipse Easy to use Provide excellent results

6. Little Eye

7. Trepn™ Plug-in for Eclipse Benefits Power at battery CPU cores and frequency Network states and usage Display and GPU GPS and Bluetooth state Wakelock and Wifilock states Tool Requirements: Eclipse + ADT plugin Android SDK Tools Android Platform-tools A version of the Android platform A version of the Android system image for the emulator or just a device Android ADB interface driver Trepn Plugin

8. This device is a digital USB ammeter that allows you to measure current automatically. It can provide quite precise digital measures (2 mA, 1%). It works with direct current (DC) as well as alternating current (AC) for which it provides the RMS value (5 mA or 3%). This device is isolated, which means that the sensing part is electrically disconnected from the USB part: you can measure any current including from the mains, without risk of frying your computer. The modules provides immediate reading on USB, and can also store measures on the device internal flash for later retrieval when connected again by USB.

9. Power consumption measurement Best Practice Display brightness Applications and services running in the background WiFi, GPS, BlueTooth can drain significant amount of power. USB devices should be disconnected during power measurement Power dissipation of loudspeaker Avoid moving the device will activate different sensors and associated device drivers to process those sensors output.

10. Q&A