Generating constant power: wearable gadgets powered by your basic movements

By Peter Murphy

The project was initiated by the Buffalo Blue Sky program, with the help of two additional senior advisors: Krishna Rajan, Erich Bloch Chair, SUNY Distinguished Professor and Empire Innovation Professor and of the Department of Materials Design and Innovation, and Andrew S. Whittaker, SUNY Distinguished Professor in the Department of Civil, Structural and Environmental Engineering (CSEE).  

“One of the important technological challenges is to have a long-lasting battery technology for VR, or other devices such as headsets or wearable sensors, so users can enjoy them for longer times without pausing to recharge their gadgets,” Seo says. “Our technology could offer a nearly ideal 24/7 operational continuous power solution to VR-enabled wearable devices.”

Seo and Jongmin Shim, associate professor, CSEE, are developing 3D Piezoelectric Energy Harvesters (PEHs). The proposed research utilizes piezoelectricity as an active material to generate power. Piezoelectric materials accumulate electric charges in response to applied mechanical stresses. These materials already exist, but Seo and Shim’s device uses a 2D-3D transformation technique with a pre-stretched substrate to produce continuous power at a higher rate.

“The transformation is similar to a 3D pop-up card. The pop-up structure piezoelectric layers have different weight and dimensions and are attached to the arch-shaped backbone of the device. This allows the PEHs to generate substantially lower resonance frequency and wide bandwidth,” Seo says. “Our 3D-PEHs can continuously produce significantly higher power by a variety range of motions and environmental vibrations, including, sleeping and breathing, walking or jogging, and vibrations from environments.”

The 3D PEHs developed by Seo and Shim address one of the fundamental challenges associated with traditional PEHs. In order to function, piezoelectric power solutions maximize their power efficiency at their own resonant frequencies. There is often a mismatch between the resonance frequencies of PEHs and ambient vibrational frequencies like human body movements. The disconnect prevents PEHs from capturing any energy from these movements. Seo and Shim’s 3D PEHs widen the frequency band and can generate energy with maximum efficiency through any type of vibration or movement humans initiate.

When combined with the motions Seo suggests, the 3D PEHs can produce enough electricity to power small portable devices, such as VR goggles and headsets, with the wide range of vibrations and motions that the human body creates (sleeping, breathing, walking or jogging). The researchers believe the power level of their 3D PEHs can be increased by connecting more units and could power larger wearable devices.

According to Seo, 3D PEHs could also become a power source for some devices currently using batteries, diminishing electronic and battery waste.

“Unlike typical solid-state batteries, the proposed 3D PEH is an almost semi-permanent power solution when there is a small vibration,” Seo says. “The success of our research can help reduce the battery waste, and also consume fewer rare earth materials.”