You can process the image with the program you prefer, in our case we prepare a simple example that allows us to move our little robot to follow the faces. Processing recognizes faces with the OCV library. When it detects a face, it draws a blue square on it. This program is very simple, the only thing it does is compare the position of the square with respect to the window. In this way the robot can know if it has to move to the left or to the right. With the size of the square the program is also able to know if the face is far or near, in this way is able to follow the faces.

On the other hand, the robot must have a microcontroller as Arduino, which allows it to receive orders from our computer (Brain) and be able to execute them in our robot (Slave).