Android devices can be used for prototyping custom devices without batteries by modifying the kernel and framework to always report the battery as full and drawing power from an external supply. This involves changing how battery level is reported and allowing higher current draw from USB to power connected peripherals. A demo is shown of running an Android phone from an external power supply without batteries.

1. Android, without batteries
Running commercial devices without batteries

2. Motivation
• Android is now the most popular OS
• Android devices have it all
• connectivity, location, processing power & multimedia
• Great choice to make solution centric custom devices
• Making custom devices is expensive!
• What if a common phone/tablet could be used for prototyping ?
• Interested ? This talk shows you how…

3. In this Talk
• A look at batteries
• How battery reporting works
• Changes required for using a power supply
• Demo
• Handling USB devices

4. What’s in a Battery ?
-ve or GND
+ve, aka Vcc (3.7V-4.2V)
Battery Detect
THERM for temperature sensing

5. Android Battery Stack
Kernel
Framework
Application
Fuel Gauge
Battery Charger
Battery
Reporting,
Actions
Higher Level
Decisions

6. Using a Power Supply
• Considerations for power supply
• Always present
• 100% level
• Modify
• Kernel
• Framework

7. Demo

8. USB Peripherals
• Often used in applications
• Supplying power is a problem
• >500 ma?
• Solution : Y cable