The commercial product appears to use an optical sensor setup, but [Salim] decided to go with a magnetic sensor setup ... into useful viewport commands for CAD software. A RP2040 is charged ...

A team of researchers has developed a pioneering 3-axis Hall-effect magnetic sensor based on an inverted pyramid structure.

3D printed holder mounted to bike wheel, fitting precisely 38 magnetic spheres around its ... He found that such a ring in front of two Hall effect sensors was low in cost, high in precision ...