How to tell if your smart phone app is power hungry

An application for the Android phone called PowerTutor is designed to let software developers build more efficient software applications. Birjodh Tiwana, codeveloper of PowerTutor and a doctoral student in the University of Michigan Dept. of Electrical Engineering and Computer Science, says the software will let users compare the power consumption of different applications and select the leanest version that performs the desired task. Users can also watch how their actions affect the phone's battery life.
PowerTutor shows in real time how four different phone components use power: the screen, the network interface, the processor, and the global positioning system receiver.
To create the application, the researchers disassembled their phones and installed electrical current meters. Then they determined the relationship between the phone's internal state (how bright the screen is, for example) and the actual power consumption. That let them produce a software model capable of estimating the power use of any program the phone is running with less than 5% error.
PowerTutor can also provide a power consumption history. It is available free at the Android Market at http://www.android.com/market/.