A computer mouse based on highly sensitive micromachined flow sensors

A PC mouse based on micromachined calorimetric flow sensors is presented. Two cylindrical openings in the bottom of the device are equipped with highly sensitive flow sensors (for the x- and y-velocity components). Due to fluid adherence to the boundary (mouse pad), the device motion induces an air-flow vortex in the cavities. A microcontroller processes the sensor signals and sends the velocity information via USB interface to the PC. In order to obtain the optimum cavity dimensions, comprehensive 2D and 3D models of the device were developed. A mouse prototype was build as a plug-and-play device and characterized utilizing a specially developed measurement setup. The measured characteristics are in good agreement with the simulated behavior. The device features very low power consumption and functions independently of the reflectivity and surface roughness of the mouse pad.