You've checked the servomotor controller and the servos. You'll now connect the motor controller to the BeagleBone Black and make sure you can control the servos from it. Remove the USB cable from the PC and connect it to the BeagleBone Black. The entire system will look like this:

Let's now talk to the motor controller by downloading the Linux code from Pololu at www.pololu.com/docs/0J40/3.b. Perhaps the best way is to log in to your BeagleBone Black using PuTTY, then type wget http://www.pololu.com/file/download/maestro-linux-100507.tar.gz?file_id=0J315. Then move the file by typing mv maestro-linux-100507.tar.gz?file_id=0J315 maestro-linux-100507.tar.gz. Unpack the file by typing tar –xzfv maestro_linux_011507.tar.gz. This will create a directory called maestro_linux. Go to that directory by typing cd maestro_linux and then type ls. You should see something like this:

The README.txt document will give you explicit instructions on how to install the software. Unfortunately, you can't run MaestroControlCenter on your BeagleBone Black. Your version of Windows doesn't support the graphics, but you can control your servos using the UscCmd command-line application to ensure that they are connected and working correctly. First, type ./UscCmd --list and you should see something like the following screenshot:

The unit sees our servo controller. By just typing ./UscCmd, you can see all the commands that you can send to your controller, as shown in the following screenshot:

Note that although you can send a servo a specific target angle, the target is not in angle values, so it makes it a bit difficult to know where you are sending your servo. Try typing ./UscCmd --servo 0, 10. The servo will move to its maximum angle position. Type ./UscCmd – servo 0, 0 and it will prevent the servo from trying to move. In the next section, you'll write some Python code that will translate your angles to the commands that the servo controller will want to receive to move it to specific angle locations.