Students will make a simple mechanical hand with a trigger connected to a hinge. Once complete, students can test the ability of their hand by trying to pick up as many straws as possible. Extra class time (and there should be plenty!) can be devoted to further testing and redesigning to make the best mechanical hand possible!
Step 1: Materials
Step 2: Build the hinge
The straw pieces act as spacers to prevent the fingers from colliding.
Step 3: Make the fingers
The two other fingers are built similarly on either side of the center finger. Make sure that the half-sticks on the outside fingers are glued on at an angle that is inverse to the center finger.
On the 'back' of the hand, glue a half-stick to the two outside fingers. These two fingers will be actuated at the same time.
Step 4: Make the arm
Once the arm length is determined, add a handle and a thumb rest at the end. The handle and thumb rest that are pictured are very minimal - there is a lot of room for innovation and customization.