I am doing a project on robotic arm. I bought OWI Robotic Arm Edge- http://www.owirobots.com/store/index.php?l=product_detail&p=110
I want it to pick things based on colour automatically. I want the arm (the different parts of the arm) to be at a default position at the beginning and want it to comeback to the same position, the parts. The arm as a whole is not moving. What kind of sensor can I use to do this, find relative position of various part of arms. A sensor that i can fix at various parts of the arm and measure the distance moved by each part or relative position between the parts.I cant use encoders on motor to measure the distance from rotation because of the assembly of the arm.
I would also like to know what kind of sensor can I attach to the gripper to know when it touches something - a pen for example.