The maker James Bruton created a 3d-printed gripper with a three-finger design and three servo motors controlled by and Arduino Uno sbc.
The design is ideal for gripping a variety roundish parts, and is held open by default with bungee cords attached to the outside like tendons. When you need it to grip something, a trio of metal gear servos pulls on cords attached to the inside of each of the three gripping fingers. Tuning the servo/gripper assembly is accomplished with an Arduino and a potentiometer for user interface.
In order to make it react to how much force is placed on an object, he inserted a spring in between the lengths of cord used to pull the device closed, and added a bend sensor that allows him to correlate servo input to finger output.
Arduino code for the build is available here. Watch the video below for more information.
