Pixy cam have not ros package but you can filnd https://github.com/jeskesen/pixy_ros to control pixy cam.
But that's package only acquire block data and control servo motor using rostopic "servo_cmd".
I'm also find https://github.com/erlerobot/erle_pixy repo to acquire image using ros node with opencv.
But that's package doesn't have servo control.
How can I control servo motor using erle_pixy?
Would you please advice to me?