Stretchable multimodal deformation sensor with self-mode recognition by a single Hall sensor

Stretchable sensor technologies capable of tracking multiple deformation modalities have attracted increasing attention due to their potential ability to improve the intelligence of soft robotics, stretchable electronics, and other soft-body systems. Existing multimodal deformation sensors typically require either complicated system integration and sensor layout or complex algorithmic techniques based on computational modeling and machine learning methods. Here, we report a stretchable multimodal deformation sensor that can measure and distinguish the magnitudes and modes of mechanical deformation (stretching, bending, twisting, and pressing) without reliance on complex computation or trained classification/regression models. This sensor relies on the layout of a stretchable magnetic film with a gradually varied magnetization profile and a 3-axis Hall sensor to decode the patterns of spatial change of magnetic flux strength under different deformation modes. We demonstrate the potential of this sensor in wearables and robotics by using it for neck motion monitoring, self-sensing electrical muscular stimulation, intelligent pneumatic gripper for objects classification, control of a stingray-inspired soft robot, and deformation recognition of an artificial elephant trunk.