Wearable Fall Detector using Integrated Sensors and Energy Devices

Abstract

Wearable devices have attracted great attentions as next-generation electronic devices. For the comfortable, portable, and easy-to-use system platform in wearable electronics, a key requirement is to replace conventional bulky and rigid energy devices into thin and deformable ones accompanying the capability of long-term energy supply. Here, we demonstrate a wearable fall detection system composed of a wristband-type deformable triboelectric generator and lithium ion battery in conjunction with integrated sensors, controllers, and wireless units. A stretchable conductive nylon is used as electrodes of the triboelectric generator and the interconnection between battery cells. Ethoxylated polyethylenimine, coated on the surface of the conductive nylon electrode, tunes the work function of a triboelectric generator and maximizes its performance. The electrical energy harvested from the triboelectric generator through human body motions continuously recharges the stretchable battery and prolongs hours of its use. The integrated energy supply system runs the 3-axis accelerometer and related electronics that record human body motions and send the data wirelessly. Upon the unexpected fall occurring, a custom-made software discriminates the fall signal and an emergency alert is immediately sent to an external mobile device. This wearable fall detection system would provide new opportunities in the mobile electronics and wearable healthcare.

Stretchable Porous Carbon Nanotube‐Elastomer Hybrid Nanocomposite for Harvesting Mechanical Energy

“…Compared to previously reported TENGs, it possesses the following features. [1][2][3][4][5][6][7][8] Energy harvesting techniques that can capture ambient energy are promising for use as sole or supplementary power sources that satisfy these requirements. Second, it has an all-in-one structure with neither multiple components nor relative motions between them, which greatly simplifies the device structure.…”

Nanomaterial‐Based Soft Electronics for Healthcare Applications

“…The demand for fabric‐based wearable electronics in healthcare, particularly in mobile and military medical applications, is continuously increasing owing to their various advantages; they are easily attached on and/or detached from clothes, are highly portable and easy to wear, offer minimal discomfort to the patients and users, and are capable of continuously monitoring bio‐signs with a high signal‐to‐noise ratio . Relatively thick and bulky energy storage modules including batteries can also be easily mounted on the fabric.…”

“…As shown in Figure d, TENGs located in the armpit region produce electricity by the friction induced from swing motions, and the supercapacitor positioned in the chest stores the electricity, which is supplied to sensors . A wearable fall detection system was also developed by combining TENGs, stretchable lithium ion battery, electronics (i.e., accelerometers/microcontrollers), and Bluetooth modules (Figure e) . Furthermore, a hybridized electromagnetic TENG, which can be used as flashing shoes, was recently employed for harvesting energy more efficiently during walking (Figure f) …”

“…Inset showsmagnified SEM imageo fc onductors. l) SBS/Ag nanoparticle-based ultrasensitive pressure sensors.R eprinted from Ref [23,24,25,19,21,26,27,28,29,30,31,32]. with permission.…”

Automatic Identification of Systolic Time Intervals in Seismocardiogram

“…These vibrations can be acquired by small and cost-effective accelerometers, which makes acquisition of SCG in wearable configuration feasible345. Further, the accelerometer employed to sense SCG can simultaneously be used in other applications such as long-term monitoring for chronic obstructive pulmonary disease (COPD) patients10, classification of breath disorders11, gait assessment for Parkinson’s disease patients12 and fall detection1314 etc. SCG finds its applications in monitoring left ventricular function during ischemia15, magnetic field compatible alternative to ECG for cardiac stress monitoring16, Diagnosis of Ischemia in Patients1718, detection of early-stage hemorrhage19 and atrial flutter20 etc.…”