Affordable & Wearable Tool for Monitoring Human Motion

The concept of developing the ideal wearable device for monitoring heart rate, muscle movement, and other feeble bio-signals without investing higher cost has motivated the researchers to search for a more affordable and simple tool.

At present, scientists from UBC’s Okanagan campus have devised a practical method for monitoring and interpreting human movements, which might bridge the gap in the area of wearable technology.

According to Professor Homayoun Najjaran from the School of Engineering, the study which began as a research to develop an ultra-stretchable sensor became an advanced inter-disciplinary project, culminating in a smart wearable device with the potential to sense and perceive complicated human movements.

The sensor is developed by impregnating graphene nano-flakes (GNF) into a rubber-like adhesive pad. Then, the tiny sensor’s durability was investigated by stretching it to check whether it can maintain precision under strains of nearly 350% of its original state, stated Najjaran. The device underwent over 10,000 cycles of stretching and de-stressing while sustaining its electrical stability.

We tested this sensor vigorously. Not only did it maintain its form but more importantly it retained its sensory functionality. We have further demonstrated the efficacy of GNF-Pad as a haptic technology in real-time applications by precisely replicating the human finger gestures using a three-joint robotic finger.

Professor Homayoun Najjaran

The aim of the team was to create a device with a reasonable size and with the ability to stretch, stay flexible, and have the needed production cost, sensitivity, robustness, and performance. According to Najjaran, in contrast to an inertial measurement unit, an electronic unit evaluating force and movement and using a majority of the step-based wearable technologies, the sensors have to be adequately sensitive to respond to distinctive and complicated body movements. The movements include infinitesimal motions, such as a heartbeat or a twitch of a finger, and also large muscle movements while walking and running.

Mina Hoorfar, the co-author of the study and Professor at School of Engineering, stated that the outcomes of the study might assist manufacturers in developing the subsequent level of health monitoring and biomedical devices.

“We have introduced an easy and highly repeatable fabrication method to create a highly sensitive sensor with outstanding mechanical and electrical properties at a very low cost,” stated Hoorfar.

In order to exhibit the practical usage of the device, the team developed three wearable devices— a wristband, a knee band, and a glove. The wristband had the ability of monitoring heartbeats by sensing the arterial pulse. The knee and finger bands worked in an entirely distinctive range of motion and monitored larger scale muscle movements while running, walking, standing up and sitting down, and finger gestures. According to Hoorfar, the outcomes of the study suggest that a low-cost device with a higher level of selectivity, sensitivity, and durability.

Hoorfar and Najjaran are both members of the Okanagan node of UBC’s STITCH (SmarT Innovations for Technology Connected Health) Institute that develops and tests sophisticated wearable devices.

The Natural Sciences and Engineering Research Council partially funded the study. The study has been recently published in the Journal of Sensors and Actuators A: Physical.