Demonstration of the human-machine interaction. (a) The voltage dividing circuit. (b) Schematic of the sign language recognition and feedback system. (c) Photographs of the sign language hand gestures (A, E, M, N, and S) according to American Sign Language. (d) The corresponding voltage profiles. (e) A high recognition rate was obtained for Chinese gestures. (f) Photographs showing that the gestures were translated into images and displayed through the LED lattice screen. (g) Sound signal for speech playing. The amplitude was normalized.