BMK Stick: IMU-Based Motion Recognition Air Mouse and Five-Multikey Keyboard

Abstract

BMK stick, a Bluetooth mouse with a keyboard is a joystick-type input device based on an inertial measurement unit (IMU) sensor that recognizes human hand movements along with the combinations of five buttons and enables users to input text with one hand. It is designed as an input device for computers and virtual environments. The BMK stick has two modes, mouse mode (mode 0) and keyboard mode (mode 1), which can be set by pushing a button. In mode 0, the IMU sensor extracts the value of the user’s hand motion with the 3D Euler angle. The extracted values are then converted into two-dimensional Cartesian coordinates through a built-in algorithm in the microcontroller unit (MCU). The converted value is mapped onto the computer screen to control the mouse pointer. In mode 1, text can be entered with with one hand using a five-button combination by using an AEIOU key-map provided by a commercial text-entry device, TAP. Two experiments were conducted to evaluate the performance of the BMK stick. In the first experiment, the mouse pointing performance was compared with three existing commercial ones. In the second experiment, the text-entry rate was evaluated in words per minute (WPM) compared with the two existing commercial one-handed keyboard input devices. The result shows that our proposed device in the first experiment performed better than the other commercial products. In the second experiment, even though some experimenters had some difficulties in manipulating our device, it produced more WPM than the commercial ones.