:: fleeing mouse ::
overview | technical
Mouse case. By replacing the tracking mechanism of a regular computer mouse with two miniature DC motors and a third "trailing" (or "leading") non-motorized wheel, this well known input device is turned into an output device.
A small weight (not shown in the picture) was added at the center of the mouse to ensure proper friction between the rubber wheels and the table.
Motors. The selection of the right motors was tricky. Non geared motors are not strong enough to move the mouse case, but most geared motors are way too big to fit into a case. We ended up using miniature geared DC motors.
Control. To control the two DC motors, the exiting four wires found in the original mouse cord are used. The polarity of the voltage and its' pulse frequency control the direction and speed of rotation of each individual motor. By combining different speed ratios, any maneuver from straight (or backwards) motion to in-place turns can be achieved.
Navigation. The location of the mouse is tracked by a webcam that is mounted above the installation. Using a negative-feedback loop, the voltage to the motors is continuously adjusted to close the gap between the current motion vector of the mouse (shown in red) and the desired vector towards the "mouse hole" (shown in green). The center of the mouse is marked by a red square. The error angle (E=xxx) and target distance (TD=xxx) are also shown.