MIT researchers have developed a battery-free, self-powered sensor that can harvest energy from its environment. (Image: Christine Daniloff, MIT)

MIT researchers have developed a battery-free, self-powered sensor that can harvest energy from its environment. Because it requires no battery that must be recharged or replaced, and because it requires no special wiring, such a sensor could be embedded in a hard-to-reach place, like inside the inner workings of a ship’s engine. There, it could automatically gather data on the machine’s power consumption and operations for long periods of time.

The researchers built a temperature-sensing device that harvests energy from the magnetic field generated in the open air around a wire. One could simply clip the sensor around a wire that carries electricity — perhaps the wire that powers a motor — and it will automatically harvest and store energy which it uses to monitor the motor’s temperature.

“This is ambient power — energy that I don’t have to make a specific, soldered connection to get. And that makes this sensor very easy to install,” said Steve Leeb, the Emanuel E. Landsman Professor of Electrical Engineering and Computer Science (EECS) and Professor of Mechanical Engineering, a member of the Research Laboratory of Electronics, and senior author of a paper on the energy-harvesting sensor.

In the paper, which appeared as the featured article in the January issue of the IEEE Sensors Journal, the researchers offer a design guide for an energy-harvesting sensor that lets an engineer balance the available energy in the environment with their sensing needs.

The paper lays out a roadmap for the key components of a device that can sense and control the flow of energy continually during operation.

The versatile design framework is not limited to sensors that harvest magnetic field energy, and can be applied to those that use other power sources, like vibrations or sunlight. It could be used to build networks of sensors for factories, warehouses, and commercial spaces that cost less to install and maintain.

“We have provided an example of a battery-less sensor that does something useful, and shown that it is a practically realizable solution. Now others will hopefully use our framework to get the ball rolling to design their own sensors,” said lead author Daniel Monagle, an EECS graduate student. Monagle and Leeb are joined on the paper by EECS graduate student Eric Ponce.

John Donnal, an Associate Professor of weapons and controls engineering at the U.S. Naval Academy who was not involved with this work, studies techniques to monitor ship systems. Getting access to power on a ship can be difficult, he said, since there are very few outlets and strict restrictions as to what equipment can be plugged in.

“Persistently measuring the vibration of a pump, for example, could give the crew real-time information on the health of the bearings and mounts, but powering a retrofit sensor often requires so much additional infrastructure that the investment is not worthwhile,” Donnal added. “Energy-harvesting systems like this could make it possible to retrofit a wide variety of diagnostic sensors on ships and significantly reduce the overall cost of maintenance.”

In the future, the researchers plan to explore less energy-intensive means of transmitting data, such as using optics or acoustics. They also want to more rigorously model and predict how much energy might be coming into a system, or how much energy a sensor might need to take measurements, so a device could effectively gather even more data.

For more information, contact Abby Abazorius at This email address is being protected from spambots. You need JavaScript enabled to view it.; 617-253-2709.