Tactile sensors are required for various robots. In humanoid robots, softness is an important feature for physical damage prevention and for interacting with the human. Moreover, if the sensor is made of stretchable material, the sensor is unbreakable and can be put on curved surfaces and joints easily. This paper proposes a novel tactile sensor which is flexible and stretchable because it is made of soft material. The sensor utilizes static electricity and electrostatic induction phenomenon, and can detect some touch conditions. Detail of principle and basic characteristics of the proposed sensor are reported in the paper. Experiments show that the sensor output depends on touch area, touch velocity, and material of touch objects. However, the sensor does not depend on touch weight. Moreover, an experiment shows that even if the proposed sensor is stretched, it performs as the tactile sensor.
