Ultra-adhesive electronic tattoo as a universal flexible keyboard with plug-and-play for human computer interaction

The existing human-computer interaction often presents problems such as bulky components, simple interaction methods, and poor universality. Here, we proposed a flexible electronic tattoo keyboard (FETK) system based on an electronic tattoo triboelectric nanogenerator (ET-TENG) which consist of an improved thermoplastic polyurethanes (i-TPU) and conductive silver paste. The i-TPU is fabricated by adding tributyl citrate (TBC) and calcium carbonate (CaCO₃) powder to thermoplastic polyurethanes (TPU) to improve its flexibility and wear resistance. Considering the portability in practical use, we have designed a signal acquisition circuit and several post-processing programs to obtain and identify signals from human finger touch accurately and stably. Furthermore, we proposed a dual-mode/multi-channel strategy to increase the number of channels and achieve one-to-one triggering of commonly used keyboard keys. Finally, we demonstrated the interactive process of using it as a keyboard to control computer output. It is worth mentioning that the FETK system we prepared can be used as a universal keyboard for plug-and-play portable use.