I designed the original prototype for this underactuated robotic hand as a fun side project during the first couple months of my senior year. After ordering all the electronics and mechanical parts in the mail, I borrowed my high school’s 3D printer and assembled, programmed, and tested the project over a caffeine fueled school break. It worked surprisingly well; in fact, it was capable of opening doors and picking up everything from pieces of paper to glasses of orange juice.

OriginalGripper

The original prototype.

However, there were a number of improvements I wanted to make: making the gripper and glove controller wireless, increasing the grip strength, covering the gears for safety and aesthetics, and adding haptic feedback. To help me make these changes, I enlisted the help of my friend Sam Baumgarten, who I’ve worked with on numerous projects throughout highschool — from homemade rocket fuel to FIRST Robotics.

The second prototype.

The second prototype.

Relying on my experience from the first gripper, research online, and our combined experience as makers, we worked together to completely redesign the hand in SolidWorks. After a couple months of improvements, revisions, and tweaks, we ordered all of the electronics, gears, and 3D printed parts. I machined various other parts — including the twelve joint shafts — in our school’s machine shop, and then stashed them away while we waited for everything to arrive. Assembly took us only a couple days, but the electronics required an immense amount of soldering, dragging out our build time. We ran into a few issues along the way, from servos and wires not fitting properly in the hand to problems with the gears meshing, but we were able to fix everything with a Dremel tool, hand drill, and super glue. The final product worked even better than we had expected. The haptic feedback and individual servo control complimented the increased grip strength, enabling us to pick up a variety of objects with ease, including apples and hand drills as seen in the video below.