Wearable triboelectric nanogenerator for real-time IoT-supported security applications

Abstract

Nanosensors are useful for monitoring human behavior and it helps to intimate the dangerous situation to get help from a trusted person. It could bring safety precautions to avoid kidnaps, robberies, and misbehaviors. Requirements like portable, wearable, and power consumption might be the hurdles to the progress of such sensors. Here we prepared a biomechanical energy-scavenging triboelectric nanogenerator, using a sponge-structured Eco-Flex polymer film. It can work as an energy harvester and as a Self-powered sensor for the first time in a wristwatch for security applications. Here sugar granules assisted as a template to develop a sponge structure that is of low-cost approach to create a porous polymer film, which is lightweight, and has high flexibility. A pair of sugar-granules-assisted sponge-based triboelectric nanogenerator (SGAS-TENG) devices could detect external motions from the wearer or from the attacker who attempts to hold the wrist. The SGAS-TENG device can scavenge mechanical energy for powering low-power electronics like LEDs, LCDs, digital watches, and temperature sensors. The electrical output is generated under different types of holding action, and the best outcome is ∼37 V and ∼ 0.5 μA with a maximum peak power density of ∼464.21 μW/cm3. A real-time transmission for security applications was demonstrated by integrating the TENG device with the ESP8266 Wi-Fi module, IoT cloud, and the mobile application Blynk 2.0. The device is analyzed for scavenging mechanical energy from the ball pressing to help arthritis patients who have less sense of grabbing in their hands. The output generated by integrating the device in a foam-based smiley ball is ∼10 V. Finally, this approach could bring systematic information about the person in danger who has hand disorders and needs physical as well as medical help.