In this paper, we introduce a wireless musical interface driven by grasping forces and human motion. The sounds generated by the traditional digital musical instruments are dependent on the physical shape of the musical instruments. The freedom of the musical performance is restricted by its structure. Therefore, the sounds cannot be generated with the body expression like the dance. We developed a ball-shaped interface, TwinkleBall, to achieve the free-style performance. A photo sensor is embedded in the translucent rubber ball to detect the grasping force of the performer. The grasping force is translated into the luminance intensity for processing. Moreover, an accelerometer is also embedded in the interface for motion sensing. By using these sensors, a performer can control the note and volume by varying grasping force and motion respectively. The features of the proposed interface are ball-shaped, wireless, and handheld size. As a result, the proposed interface is able to generate the sound from the body expression such as dance.