fig5

Figure 5. Demonstration of the portable paper-based device. (A) Photo illustrating a representative usage scenario of the portable paper-based device (author team members shown; photographed by the authors); (B) Photo showing detailed information on the two portable circuit boards (photographed by the authors); (C) Block diagram illustrating the operational workflow of the paper-based device integrating the haptic feedback unit and loudspeaker unit; (D) Results demonstrating the fidelity of the paper-based device in different musical scales; (E) SPL values corresponding to the different musical scales; (F) Vibration displacement in response to different musical scales, indicating that the haptic feedback unit produces stimuli that are easily perceived by human fingers; (G) The waveforms of Two Tigers performed by volunteers in different groups. The error bars represent the standard deviation, with an experimental sample size of three. SPL: Sound pressure level; MCU: microcontroller unit; GPIO: general-purpose input/output; PWM: pulse width modulation; HV: high voltage; PHL: passive haptic learning.