|Robotic Finger with Servo|
You need a standard SG90 Servo. Press it in and set it´s poisition to 0°, than put on the Servo arm so the string is the shortest.
Knot the string to the servo arm and fix the string to the fingertip, i used an 2mm Screw.
Now you can use an arduino to move the servo from 0° (opened finger) to 180° (closed finger). Use the Servo Library for this purpose.