Human–machine interactions (HMIs) have advanced rapidly in recent decades in the fields of healthcare, work, and life. However, people with disabilities and other mobility problems do not have corresponding high-tech aids for them to enjoy the convenience of HMIs. In this paper, we propose a sensor with a wave-shaped (corrugated) electrode embedded in a friction layer, which exhibits high sensitivity to skin fold excitation and enormous potential in HMIs. Attributing to the wave-shaped electrode design, it has no built-in cavities, and its small size allows it to flexibly cope with folds at different angles. By specifying the carbon nanotube hybrid silicone film as the electrode layer material and silicone film as the friction layer, good electrical output performance, tensile properties, and biocompatibility can be achieved. Then, the sensor is tested on various joints and skin folds of the human body, the output signals of which can be distinguished between normal physiological behavior and test behavior. Based on this sensor, we designed a medical alarm system, a robotic arm assistive system, and a cell phone application control system for the disabled to help them in the fields of healthcare, work, and life. In conclusion, our research presents a feasible technology to enhance HMIs and makes a valuable contribution to the development of high-tech aids for the disabled.