Bioimpedance-driven haptic feedback for human-computer interaction

This work presents a novel method for establishing a feedback loop in future human-computer interactions by using bioimpedance measurements to enhance the sense of physical engagement. The proposed system consists of a bioimpedance measurement unit, a vibration motor, an inertial measurement unit (IMU) and a Bluetooth wireless communication module. By measuring the bioimpedance of flexor digitorum muscles, the system estimates the hand's grasping angle and applied force independently. To address the drift commonly observed in long-term bioimpedance measurements, the rate of change in bioimpedance is used instead of absolute values. The bioimpedance change rate-based method achieved a linear coefficient of determination (R2) of 0.9845. Vibration motor rotational speed is then modulated in real time based on either the estimated hand grasping angle or force magnitude, depending on the application. The proposed haptic feedback bridges a key limitation of traditional vision-based interaction methods, which are unable to detect force, thereby enabling a more immersive interaction experience. The entire system is implemented as a wearable Bluetooth human interface device (HID), ensuring compatibility with a range of commercial consumer electronics.