Energy harvesting has experienced significant growth over the past few years due to the ever-increasing desire to produce portable and wireless electronics with extended lifespans. This has lead to many academic groups working on developing energy harvesting technologies.
For industrial applications the use of batteries can be troublesome due to their limited lifespan - imagine the cost and work involved in having to change hundreds of batteries in sensors scattered across a busy bridge.
Now Kansas State University are working with Peregrine Semiconductor, on an energy-harvesting radio that could transmit important data such as stress measurements on a bridge without ever having to change the batteries.
The scientists have been working on the project for just over a year and have created a demonstration board constructed using solar cells from cheap calculators to power the radio. The board has capacitors that capture and store the light energy to power the radio without a battery and includes a microprocessor to store data before it's transmitted via radio.
When the stored data is ready to be transmitted, the radio sends out a data-burst every five seconds that a computer can translate into meaningful information, such as telling an engineer the stress or strain on the underside of a bridge - like sending a text message from one cell phone to another: After data are transmitted through the air, the recipient's cell phone turns that data back into text that can be understood.
The radio used is the "Mars chip" that Bill Kuhn, K-State professor of electrical and computer engineering and a team from K-State, Cal Tech's Jet Propulsion Laboratory and Peregrine Semiconductor helped develop in a successful project for NASA. They developed a micro transceiver to use on Mars rovers and scouts. In 2007, the work was published in Proceedings of the Institute of Electrical and Electronics Engineers.
The engineers are looking at which frequencies to use based on how the environment affects radio waves indoors versus outdoors. They also have to look at how noise and other factors may limit the sensitivity of the receiver that's getting the data from all of the sensors.
Because these sensors save data in their microprocessors, they are working on timing and wake-up commands that tell the sensors when to send the stored information to the receiver. Through engineering analysis, they are determining tradeoffs between power requirements, data-rate and transmission range issues.
Although the prototype captures and stores light energy, the scientists say that energy-harvesting radios could be powered by a number of different ways, including electrochemical, mechanical or thermal energy.
Top image: An in-progress demonstration board of an energy-harvesting radio developed at Kansas State University. The finished board includes solar cells to power the radio. (Photo courtesy of K-State's department of electrical and computer engineering)
Reference: Kansas State University
For more attend Printed Electronics Europe 2009 and read Energy Harvesting and Storage for Electronic Devices 2009-2019.
