There is terrific research being conducted on flexible hybrid electronics (FHE) at the university level. Professors and researchers are partnering with governing bodies and industry leaders to create the sensors and wearables of tomorrow. Auburn University is one of the leading colleges in the field of FHE, and its latest project, a biometric band, offers much promise.

Dr. Pradeep Lall, professor of mechanical engineering and a John and Anne MacFarlane Endowed Distinguished Professor and Director at Auburn University, is leading the project in conjunction with Optomec.

“The concept in the project is a biometric band made up of a wearable flexible band with an onboard microcontroller,” Dr. Lall said. “This is used to acquire analog signals from human body sensors such as the pulse-oximeter, inter-beat interval, and electromyography. The flexible band is sized to fit on a wrist and is of the size of a typical shirt-cuff.”

Dr. Lall noted that a prototype of the device has been fabricated and an Android platform-based application has been developed for the implementation of the system. This device monitors sudden changes in biometric information, such as pulse and muscle activity in users, and connects to an Android phone via a Bluetooth module to call 911, if necessary. The device is intended to decrease paramedic response times during emergencies.

“Reducing paramedic response times to five minutes could nearly double the survival rates of patients experiencing life-threatening medical conditions,” he reported. “Maintenance of an independent lifestyle with a comparable level of monitoring requires the development of devices, which can provide continuous monitoring and timely medical intervention when needed, without the tie-down constraints of a hospital setting.”

The design was conceived and developed by Dr. Lall at Auburn University’s NSF-CAVE3 Electronics Research Center.

“Auburn University has been working under a NextFlex Project with partner Optomec and others on test protocols for FHE materials and devices to develop FHE systems that could stand up to wear, abrasion and human sweat and saliva. In addition, the Auburn University team is working with material suppliers and molding companies to fine-tune the materials and molding solution that would allow for flexible printed electronics solution while ensuring biocompatibility in conjunction with passivation for electronics, and survivability in operation.  Manufacturing recipes developed by the Auburn University team will enable high volume scale-up of the flexible printed electronics process,” he noted. 

One of the key advantages of flexible hybrid electronics is its ability to be designed into conformable systems that can be worn comfortably and unobtrusively.

“The use of flexible hybrid electronics (FHE) technology allows for the band to be readily worn,” Dr. Lall explained. “Traditional electronics manufacturing uses rigid printed circuit boards for fabrication and planar technology for fabrication. A rigid design would have limited integration into a wearable form factor. However, the use of flexible electronics technologies allows for use of a flexible, bendable, twistable design that can perform reliably under the stresses of daily motion while at the same time being comfortable to wear. Flexible electronics also allow for the design of non-planar architectures that can conform to the human body.”

Dr. Lall pointed out that traditional rigid electronics use glass-epoxy impregnated circuit-board materials for the formation of circuits, attachment and interconnection of components, adding that the use of glass-epoxy impregnated laminate does not lend itself well to flexing, bending, twisting and folding without catastrophic failure of the printed circuit board.

“In contrast, the biometric band is made on a flexible substrate of polyimide, which allows for processing temperatures over 300℃ while allowing for bending, twisting, folding and flexing in the end application in the neighborhood of room-temperature to human body temperature as the band is worn on the user’s wrist,” he noted. “The ability to achieve flexibility is attained through new innovative materials, processes, interconnect technologies, and encapsulation methods to allow for flexibility while maintaining structural integrity.”  

Ultimately, Dr. Lall sees the biometric band being an ideal device for consumers, athletes and in the workplace.

“The concept is intended for the wearable consumer market,” he observed. “The band could be used for monitoring in a number of applications. In one application, the band would be used by athletes training on trying-terrain to allow for continuous health monitoring of vitals while providing an autonomous way to assist in case of a mishap. In a second application, the band would be used by workers operating in hazardous environments. For example, workers inside aircraft fuel tanks where accidental inhalation of fumes could be fatal would be able to use the band. The biometric band would allow for continual monitoring of the user’s health, allowing for autonomous alarms both locally and remotely to call for immediate medical intervention. A third application would be for use by the elderly who live alone to provide medical oversight or timely intervention when needed.

“Our eventual goal is to partner with a high-volume manufacturer to commercialize and bring the band to market,” Dr. Lall concluded. “Given the multiple applications in which it could be used, we feel the device has a huge potential.”