How it works: claw opens and waits for color sensor to not sense black. When it senses a color, the claw closes, drags the item to the bag, and drops it into the bag. If you want to see it in action, you should watch the movie. There are two motors, a intelligent brick, and a color sensor in the robot. In the claw, I added two small gears that turn two large gears, which makes the claw stronger, so it can pick up heavier items.