ENERGIZED: ME Ph.D. students Eli Leland and Elaine Lai have been working on harnessing energy from the environment to power the sensor technology that Center for Information Technology Research in the Interest of Society (CITRIS) researchers have been working on.

ME students try to make energy from footsteps

The research going on at Berkeley in sensor-related technology portends a future where these mini computers will be everywhere, collecting data on everything from temperature and light readings to traffic flow and the spread of fires.

If these sensors are to enjoy the kind of ubiquity that engineers envision, they will need to be powered by a low maintenance energy source. Traditional battery and electrical power would need to be checked, replaced and maintained by users.

That’s where ME Ph.D. students Eli Leland and Elaine Lai come in. They are looking at ways of gleaning enough energy from the environment to self power each sensor.

Like a cliche, B-movie example of a mad scientist harnessing the energy of a laboratory hamster as it runs on it’s exercise wheel, the two ME students are trying to prove that they can collect enough electricity from natural and environmental sources to power small appliances.

Their latest test bed in the underbelly of the rickety wooden staircase of the Naval Architecture Building, where theyplaced a sensor the size of a hockey puck to take temperature readings around the clock.

The temperature sensor will then beam the information it collects to another computer for data crunching.

“We are trying to simulate a wooden staircase in a house. We are hoping that the vibration caused by footsteps on the stairs will power this temperature-reading device,” says Leland.

To turn vibrational energy into electrical energy, the students are using piezoelectric material, which stretches and compresses when it senses vibrations. These contractions create a continuous energy source.

“We are trying to integrate electricity generation with an actual temperature sensor. This experiment is just to see if it is possible,” adds Lai.

Their project was the thesis work of Berkeley ME alum Shad Roundy. Lei and Leland are picking up where Roundy’s research left off.

If their experiment is a success, they will start working on creating smaller and smaller devices that can convert ambient energy into power.

“In our field, bigger isn’t better. One day we would like to create sensors the size of dust,” says Lai.

The microscale they strive for is part of Berkeley’s leading microelectro mechanical systems (MEMS) research effort. Berkeley students are using MEMS to make technology not just smaller but also cheaper.

“We would like to fabricate these self-powered sensors like microchips are currently made. This would drive down the cost per device. The goal is to produce millions of these sensors at the cost of 10 cents apiece,” says Lai.

Self-powered sensors could be left in place indefinitely. The result is a low-maintenance, aesthetically pleasing device, says Leland.

At a time when the California Energy Commission is urging the reduction of power at peak times, the Berkeley ME research effort is looking for ways to use energy more efficiently.

“The technology that would enable self-powered sensors is something that can change the world,” says Leland.

For more about the project, e-mail eli@kingkong.me.berkeley.edu or emlai@kingkong.me.berkeley.edu.

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