We decided not to use a webcam and vision detection. We just do not have enough time between now and the state tournament to learn how to implement them. Here is what we did do.
We installed our arm and color sensor to handle skystones during autonomous. We used a Rev Robotics Core Hex motor to drive the arm since it provides for a more secure grip than does a servo. A secure grip is important since we plan on sliding the skystones along the mat to move them. We also chose a Modern Robotics color sensor since we had more information available to help us write the program to detect skystones. The distance sensor is a Rev Robotics 2m distance sensor. See below.