Wireless Sensors without Batteries

Efficient homes are quickly becoming a reality. This is achieved through combinations of sustainable energy and more efficient design. Getting the most out of these designs still requires the user to be as efficient as the building. Thanks to new sensor technology, home energy systems may get even smarter and make  it easier to reduce energy use.

Though some of the most advanced house designs are very user friendly, there are still improvements to be made. Most of the “smart” features are based on optimizing energy use around human activity. This includes lights that turn off when you leave a room and heating and cooling that is individualized to certain spaces and only operational at peak times.

The key to these technologies is tracking use and need. Sensors are required to determine conditions and activity, but they use power as well, which can make them difficult to place. That is where Philip Feng, an assistant professor of electrical engineering and computer science at Case Western Reserve University is looking to take efficiency a step further.

As described in a Case Western News article, Feng has received an incubator award from the US Department of Energy to develop piezoelectric resonant devices that can run on vibrations that occur during normal building use.

Some of the areas possible for energy “scavenging” are the motion of a swinging door, vibrations from TV speakers, refrigerant compressors, etc. There are a host of appliance and infrastructure possibilities when you have the right technology. The sensors can be tuned to maximize their effectiveness for individual circumstances.

As you may imagine, even a well-matched sensor cannot harvest much power from these sorts of applications, so ultra-low power circuitry for sensing and wireless communication is part of the package as well.

The goal is to create a network of sensors which can provide real-time feedback on heat, humidity, electricity usage, etc. The pertinent controls can then be controlled wirelessly by the user, or they can be programmed to automatically adjust based on current conditions.

The nickel-sized sensors can be used in existing structures by attachment using doubled-sided tape or built into new construction. Feng will be working with Kenneth Loparo, chair of the electrical engineering and computer science department, and Intwine Connect LLC, a company which has offices on campus, to improve the sensor design and optimize their use.

 

Image:  Case Western Reserve University