ThumbJoy: Using the Thumb’s Metacarpophalangeal Joint as a Joystick Input Device

We introduce ThumbJoy, which utilizes the physical movement of the left thumb metacarpophalangeal (MCP) joint along with its psychophysical qualities as a joystick. Using an inertial measurement unit (IMU), ThumbJoy avoids the restraints of hand tracking occlusion, allowing more contact area for the thumb thus providing self-haptics. We first conducted a pilot study of 20 participants to systematically analyze the characteristics of the MCP joint. Using these results, we implemented an algorithm that converts joint movement to a planar 2D axis movement. We then conducted a user study comparing ThumbJoy with conventional interaction mediums in a virtual reality (VR) environment. Through this, we demonstrate that ThumbJoy can provide an intuitive method of control while increasing immersion and enjoyment in VR along with the use of self-haptics.