Mato, using a Pixy camera, now can chase a ball.
To accomplish this, I used a Pixy camera and an Arduino. I fed the output (target color to the left or target color to the right) to Mato's primary Arduino--see the schematic below.
The Arduino sketches for Pixy and Mato are available on this site.
The camera and wiring (temporary setup--may become the tomato stem) are shown below.
Here's Mato ready to fetch.