Sustainable Biomechanical Energy Scavenger toward Self-Reliant Kids' Interactive Battery-Free Smart Puzzle

Biomechanical energy is a promising renewable energy source and, owing to the demand for portable and smart device power sources, has attracted the attention of researchers in a wide range of disciplines. We present a smart puzzle triboelectric nanogenerator (SP-TENG) based on the contact and separation mode between a surface-modified polydimethylsiloxane film and a paper contact material. The SP-TENG exhibits a simple structure (thin and lightweight), with an output voltage of 70 V and a current of 6.5 mu A, which can drive a liquid crystal display at the press of a finger. A systematic investigation of the SP-TENG demonstrated it to be a practical energy harvester with the potential to charge a commercial capacitor and drive a liquid crystal display. The SP-TENG also acts as an instantaneous force sensor with detection sensitivity of 2.605 mu A kPa(-1). We fabricated six SP-TENGs as puzzle pieces and formed a self-powered smart puzzle by connecting it to a simple logic circuit. This approach improved a simple traditional puzzle, transforming it into an interactive smart puzzle.