Researchers hope to make phone batteries last longer

NEWARK, Del. (AP) — Anyone with a smartphone knows the struggle.

Used Google Maps to chart a route home? Spent a little too long scrolling through Facebook? Played more than 20 minutes of Pokémon Go?

Chances are, there’s a dead battery in your future.

Today’s mobile phones contain more processing power than NASA used to put a man on the moon, but the lithium-ion batteries that feed those mighty pocket computers have not kept pace with our ever-increasing demand for more power.

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Phone makers across the globe are hunting for ways to keep phones working longer.

A team of researchers at the University of Delaware, meanwhile, is focusing on the other end of the equation: the power-sucking software that’s draining your battery.

“Most software developers worry about performance and user experience, but they don’t have a sense of how to make their apps more energy efficient,” computer science professor Lori Pollock said. “We’re trying to change that.”

Pollock and assistant professor James Clause are investigating how an array of common techniques used by coders might be inadvertently contributing to battery drain.

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The goal, they say, is to develop their own software capable of scouring a developer’s code for potential energy leaks and then recommend fixes.

“We also want to come up with a list of best practices so developers don’t make those mistakes in the first place,” Clause said.

The professors recently landed a three-year, $516,000 grant from the National Science Foundation, most of which will be used to pay a team of graduate and undergrad students also working on the project.

“This is actually something we’ve been working on since 2010,” Clause said. “It turns out it’s a lot more complex of a problem than it sounds.”

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One of the first challenges the team faced, he said, was figuring out how to measure the amount of energy being used by a given app without altering the very thing they were trying to observe.

“Phones have a processor, memory, a screen and sensors, all of which use energy,” Clause said. “It’s really quite difficult to get an idea of what part of the phone is using what and the people who design phones don’t make it easy to figure out what is going on.”

Next, they came up with a system for mapping how slight changes in isolated sections of code were affecting energy consumption.

More recently, the professors have tackled how to put apps through their paces in a way that eliminates the kind of random inputs that could throw off their measurements.

“You can’t have someone sit there for hours running a calculator app,” Clause said. “That would be incredibly boring, for one. But they also might take one second between taps the first time and two seconds the next time, which is going to impact the energy consumption.”

Instead, a computer on the fourth floor of UD’s Smith Hall is quietly running precise input sequences using a Sudoku game, a constellation map and other apps loaded onto an LG Nexus 4 and a Samsung Galaxy S5. At the same time, another device wired into the phones is monitoring how much energy is being used by the hardware.

After a few code adjustments, each process is run again 30 times to ensure reliable readings.

Some of the coding techniques Clause and Pollock are now examining range from simple choices, such as the colors used in an app, to far more complex interactions.

“One thing developers like to do is obfuscate their code to make it harder for people to figure out how it works,” Clause said. “Those kinds of changes might take 15 minutes of battery life, while an app that turns on GPS and maybe forgets to turn it off will drain a battery in a few hours.”

That might sound familiar to fans of “Pokemon Go,” which taps into a phone’s GPS and camera. The app is such a notorious power hog that portable battery makers are now marketing their devices to players of the popular mobile game.

While the researchers’ work could someday allow gamers to play longer, the team’s sites are set on slightly loftier goals.

“This research eventually could prove beneficial for saving power at data centers or helping future household items with network connectivity last longer,” Pollock said.

“But right now, the greatest interest is with mobile software designers,” she added. “They know people care about it, but they can’t do as good a job as they would like because they’re missing the information about the energy usage of their software and how use it in their decision-making. So that’s what we’re trying to give them.”