Researchers in Singapore have developed a method using torque oscillators to use wireless signals and convert them into energy to power small electronics. The research is published on the website of the National University of Singapore.
A research team from the National University of Singapore and Japan’s Tohoku University has developed technology that uses tiny smart devices known as torque oscillators to collect and convert wireless radio frequencies into energy to power small electronics. In their work, the researchers successfully conducted an experiment to harvest energy using Wi-Fi signals to wirelessly power an LED without using any battery.
“We are surrounded by Wi-Fi signals, but when we are not using them to access the Internet, they are inactive and this is a huge waste of resources. We decided to turn the available 2.4 GHz radio waves into a green energy source, reducing the need for batteries to power our electronics. Small electrical gadgets and sensors can be powered wirelessly using radio frequency waves over the Internet of Things. With the advent of smart homes and cities, our work could lead to energy efficient applications in communications, computing and neuromorphic systems, ”said Professor Yang Hyunsoo of the Department of Electrical and Computer Engineering at the National University of Singapore.
Torque generators are a class of devices that generate microwaves and are used in wireless communication systems. However, their use is difficult due to their low output power.
Mutual synchronization of multiple generators is a way to overcome this problem. Existing circuits, such as short-range magnetic coupling between multiple generators, have spatial limitations. On the other hand, long-range electrical synchronization using vortex generators is limited to frequency characteristics of only a few hundred MHz. Dedicated current sources are also required for separate oscillators, which can complicate the overall implementation on-chip.
To overcome spatial and low frequency limitations, the research team developed an array in which eight oscillators were connected in series. Using this array, the 2.4 GHz electromagnetic radio waves that Wi-Fi uses were converted to a constant voltage signal, which was then passed to a capacitor to power a 1.6-volt LED. The capacitor charged for five seconds, and then could power the LED for one minute after turning off the wireless power.