Here is a soft robotic gripper that doesn’t require electronics to work. Roboticists at the University of California San Diego collaborated with BASF corporation researchers to make this robotic gripper. Here is how it works:
We designed functions so that a series of valves would allow the gripper to both grip on contact and release at the right time. It’s the first time such a gripper can both grip and release. All you have to do is turn the gripper horizontally. This triggers a change in the airflow in the valves, making the two fingers of the gripper release
explained Yichen Zhai.
The robot can remember when it has grasped an object. When it detects the weight the object pushing to the side as it is rotating, it releases the item. More info is available here.