Using a servo controller to control the servos
To make your quadruped walk, you will first need to connect the servomotor controller to the servos. The servo controller you are going to use for this project is a simple servomotor controller utilizing USB from Pololu (Pololu item number 1354, available at pololu.com) that can control 18 servomotors. Here is an image of the unit:
Make sure that you order the assembled version. This piece of hardware will turn USB commands from the BeagleBone Black into signals that control your servomotors. Pololu makes a number of different versions of this controller, each able to control a certain number of servos. In this case, you may want to choose the 18-servo version, so you can control all 12 servos with one controller and also add an additional servo to control the direction of a camera or sensor. You could also choose the 12-servo version. One advantage of the 18-servo controller is the ease of connecting power to the unit via screw-type connectors...