A calibration-free self-powered sensor for vital sign monitoring and finger tap communication based on wearable triboelectric nanogenerator

Triboelectric nanogenerators (TENGs) have attracted much attention due to the high output, low cost, and environmentally friendly nature. However, wearable devices still have certain hardness due to the choice of metal electrode, which has no gas permeability, and affects the wearing comfort. In addition, the electrode does not adhere firmly to the friction material, which also affects the electric performance. We report a TENG base on ordinary fabrics with polymerizes polyaniline (PANI) as electrodes, and uses polycaprolactone (PCL) to make the fabric and friction material fit well. The TENG have excellent softness and certain gas permeability, improving the comfort of the wearable smart health monitoring. The output electrical of TENG can arrive 200 mu A and 1000 V under a frequency of 2.5 Hz. It can drive about 1000 LEDs and continuously supply power to electronic production. This truly wearable generator can provide a good information interface for critically ill patients. On the one hand, it can monitor the patient's breathing state in real time and give an alarm when the breathing stops. On the other hand, patients with language communication difficulty can also tap the finger to send messages by using Morse code. More importantly, we have experimentally proved that this self-powered sensor can still work normally with additional contact resistance, which will guarantee the long-term reliable operation of this device in a flexible environment.