Use a USB mouse for tracking planar motion. The idea being that we can easily localize a robot using something that was literally designed for tracking 2D motion.
Run sudo python3 mouse_data.py to view almost raw data coming off the mouse.
Run sudo python3 track_mouse.py to view the mouse input using Turtle. A left click will reset the state.
You can read about how Linux handles mice here.
You can turn mouse acceleration off (on Ubuntu at least) with xset m 00 and back on again with xset m 11. Note that this won't affect the values read from /dev/input/mice, but it will affect where your OS displays your cursor with respect to the robot Turtle if you're testing with a GUI.
I've attempted to separate interfacing with the mouse and visualizing (and eventually computation) into two separate classes Robot and Mouse This isn't really necessary, but Robot inherits from Turtle, which has many of the things we need, so it works fairly well.
Note that I've mapped whatever units the mouse gives to millimeters by experimentally finding 71 mm / 2600 units. This might change according to the surface we use.