I completed my design of a single axis robotic arm. The servo lifts and lowers the arm like a traditional arm. What is different is the end effector that allows the arm to pick up objects. It's a wire snare, similar to the end effector on the Space Shutter robotic arm. A mini servo extends and retracts the wire snare, letting it wrap around and tighten around th object to be picked up.
Look for a magazine article (in Servo) and a kit to made available shorty.