Simple PiCam Motion Detecting Robot Personality Behavior Notices You Coming and Going

My wife has started noticing when my GoPiGo3 robot, Carl, appears to be incommunicado.

This simple robot personality behavior implements using the PiCam, without the need for OpenCV, to detect motion, and to speak a greeting if the motion is left to right, and speak an exit response for leaving the room with right to left motion.

It should run without change on any GoPiGo3, but will quietly print the greeting/exit responses.

The code is here

If you want it to speak, this is my text-to-speech interface