1. Schematic diagram of self-powered FSO communication system based on friction nanogenerator
(a) May be used to monitor various types of mechanical signals
(b) The use of friction nanogenerators of different structures to monitor different mechanical signals and to form a FSO transmitter with LED arrays
(c) The receiver detects and demodulates the required monitoring information
2. Self-powered wireless remote control
(a) Schematic diagram of friction nanogenerator and LED connection
(b) Open circuit voltage of the friction nanogenerator
(c) Charge transfer of the friction nanogenerator
(d) Histogram of red, green and blue intensity of a typical "bright" LED image
(e) Histogram of red, green and blue intensity of a typical "dark" LED image
(f) Tetris game interface based on the designed system
3. Self-supplied wireless touch array for pressure detection
(a) Transparent array of friction nanogenerators
(b) Schematic diagram of connection between friction nanogenerator array and LED array
(c) Typical LED images under different pressures and their corresponding green component intensity histogram
(d) Green component strength fitting curve of LED picture under different pressures
(e) The corresponding pressure detected when four touch points on the diagonal are pressed simultaneously
4. Self-supplied wireless touch pad for user authentication
(a) Schematic diagram of "z-type" sliding unlock
(b) The typical intensity-time curve of user 1
(c) Radar map of feature information extracted by sliding "z font" of different users
(d) Green component strength fitting curve of LED picture under different pressures
(e) Flow chart of the algorithm for user authentication
