Project 3: MEMS Origami for Energy Harvesting at Soft Surfaces (Prof. Cindy Harnett, ECE)

Advanced manufacturing Topic:  If microelectromechanical systems (MEMS) were soft and flexible, we could use them in wearables that track human health and athletic performance in greater detail than ever before. The problem is that MEMS are typically packaged in brittle silicon. Not only that, but most sensors require batteries that do not conform to the body.  In this project students will use “pop-up” MEMS origami techniques to design, fabricate, and package brush-like arrays of spring contacts in a soft polymer sheet—taking micron-scale MEMS components to the scale of the human body. Arrays of integrated diodes will enable the brush to collect and store charges from a surface in an energy-harvesting application that charges a soft device by making contact to a powered surface. The REU will investigate the mechanical and electrical properties of the system, and will also research possibilities for harvesting static electricity as the brush moves against other soft surfaces in a body-worn system and in application environments such as a clothes dryer. They will work alongside other research staff and students in the cleanroom and Dr. Harnett’s lab  (www.harnettlab.org). Brush fabrication is performed by surface machining of silicon wafers and transfer to a polymer sheet. Students will be able to focus their work to the mechanical, electrical, or materials science aspects according to their skills and interests. This project is suited for students interested in EE, ME, Materials Science, and Physics.

Figure 1. Springy MEMS pop-ups fabricated in the U of Louisville MNTC [1]

Figure 2:Working millimeter-scale scale contact array collecting energy from a powered surface [2]. 1mm contacts and discrete diodes to be replaced with springy MEMS pop-up microcontacts and integrated diodes; hard fiberglass circuit board to be upgraded to a soft, thin polyimide film in this project. 

References

[1] Moiseeva, E., Y. M. Senousy, S. McNamara, and C. K. Harnett. "Single-mask microfabrication of three-dimensional objects from strained bimorphs." Journal of Micromechanics and Microengineering 17, no. 9 (2007): N63.

[2] Harnett, C. K. "Tobiko: A Contact Array for Self-Configuring, Surface-Powered Sensors." In Proceedings of the 2017 CHI Conference on Human Factors in Computing Systems, pp. 2024-2028. ACM, 2017.