Piezo Electric Crosswalk

Senior Design - Fall 2019

Together with a team of 5 engineers from 3 separate disciplines, I worked in Fall 2019 to develop a design for a piezo-electric crosswalk into a deployable model. The project, sponsored by the Georgia Tech Research Institute, aimed to harvest energy from vehicles through a layer of piezo-electric elements embedded beneath the roadway. The harvested energy could be used to warn drivers of pedestrians in the roadway, deliver traffic data to engineers, or serve numerous other purposes.

Protection of the fragile piezo elements from the high loads they may experience proved to be a critical consideration of the project. Of a similar importance was the ability of the system to differentiate between objects on the crosswalk such as cars, bicycles, or pedestrians. To accomplish both, a dual-density layer of elastomers was implemented, such that the desired deformation of a single plane of piezo-electric elements will be achieved when bearing the weight of a pedestrian, and a second layer will deform under the weight of a vehicle.

The optimal deformation for power generation was determined via a self-designed test regime on an Instron machine, which was capable of achieving and measuring specific forces and deformation magnitudes at a period mimicking that of a human footstep or car tire. Solar panels were added, shielded by 3/8in polycarbonate, to provide supplemental electricity generation.

With sensing and power generation questions resolved, a simple bluetooth module was outfitted to the tiles, to allow the sharing of data to nearby tiles and researchers. In this way, arrays of LED lights in front-facing tiles could be illuminated when pedestrians were present, warning cars of their presence in low-visibility scenarios. Traffic engineers could also access data logs, to view historical traffic data and improve light timing or traffic patterns.