For instance, the device could be placed in an attic or inside a wall, and sensors would be tuned to check for water leaks. Similarly, when used inside a bridge, the sensors could detect any cracks forming or structural deficiencies. In both cases, the sensors would send a signal to the nearby powered receiver.
A temperature change of only 0.25 degrees Celsius creates enough energy to power the sensor node to read and send data wirelessly to a receiver 5 meters away. That means any slight shift in an office building's air conditioning or the natural outside air temperature during the course of a day would be more than enough to activate the chemical in the bellows.
The UW's technology uses temperature changes over time as its power source. Devices called thermoelectric generators also leverage varying temperatures for power, but these instruments require a temperature difference at an exact moment, such as in a place where one side is hot and the other is cool.
The researchers have filed patents for the technology and plan to make it smaller, about the size of a D battery. A future version would include four chemicals that activate in different temperature ranges so the same device could be used in various climates.
"I think our approach is unique," said Chen Zhao, lead author and a UW doctoral student in electrical engineering. "We provide a simple design that includes some 3-D printed and off-the-shelf components. With our Web page and source code, others can download and build their own power harvesters."
|Contact: Michelle Ma|
University of Washington