3D Printing in STEM Education: Hacking the Raptor Reloaded to Create the Grab-Tor

When I was a kid, eons ago, I got a toy that was a plastic grabber on the end of a stick, controlled by squeezing or releasing a whole hand trigger in the handle. I was, as you can no doubt imagine, super cool. This grabber gave me the capacity to easily pick up, and then most likely drop, any lightweight, smallish object within a four foot radius. I was happy. Not only was it satisfying to wield such power, the closest thing I’d had to magic since an egg cracking debacle let to the confiscation of my cape and top hat, but I could also chase my younger brother through the yard in the guise of Grabtor the Evil.

Of course, back then, you had to just accept whatever $1.00 version of this delight was available, and since I grew up in rural South Carolina there weren’t many, but now with the introduction of makerspaces, one educator has realized just how much learning can come out of making your own grabbers. And I’m not even a little bit jealous that he developed the name Grab-Tor to describe the kids’ creations. The man in charge of this awesome project is Rich Lehrer and his involvement with functioning 3D printed devices is something close to his heart.

Since 2013, he has been working with his students at Brookwood School in Manchester-By-The-Sea, MA to create 3D printed prosthetic hands for his son Max who was born with an upper limb difference. Lehrer has long been immersed in the community surrounding e-NABLE. In other words, he has been fully immersed and personally dedicated to helping students learn about advanced technologies in the process of creating functioning prosthetics.

It’s a great project that gives kids a sense of purpose to learning, but it’s not so easy to build a working prosthetic hand. So, Rich started looking for ways to more gradually introduce the project without losing the sense of purpose and goal oriented nature of the prosthetic hand itself. Then, he experienced a blinding flash of the obvious:

“While in the middle of a 5th grade eNABLE unit with my colleague, Henry Oettinger, we were having the students work through a Design Squad Global project building cardboard and duct tape ‘grabbers’ to introduce some of the ideas surrounding assistive devices. Half way through the activity, we realized that if we could have the students create 3D printed grabbers based on the hands they would soon be building we would be able to provide them with increased education experiences involving designing, critical thinking, 3D modeling, and learning of STEM concepts and skills. In an instant, we had created a new educational approach that we call ‘Raptor Hacking’ in which students remix the files of existing Raptor Reloaded hands to create a grabbing Raptor or ‘Grab-Tor.'”

What ensued was a mini-project in which the students pulled Raptor Reloaded files into TinkerCAD and created a ring with knuckles on it that could be fitted over a PVC pipe. The knuckles were then connected to the fingers designed for Raptor Reloaded and the entire creation was made functional through the attachment of cords, bungee, and finger rings. Allowing the kids the opportunity to personalize their devices led to the creation of things such as the addition of bear claws. And the avenues for exploration just keep laying themselves out before Lehrer as he explores the landscape of possibilities within what was originally conceived of as a first step project.

“This week I began collaborating with Brookwood life sciences teacher, CJ Bell, on a natural selection and adaptation project in which students design removable finger extensions to change the functionality of the device in response to variations in ‘food’ (different shapes of pasta) availability. Additionally, I hope to soon be reporting about collaborations with a number of natural history organizations in which students are able to digitally scan claws, beaks, jaws, and tentacles of different animals and graft these structures onto Grab-Tors in order to both test their functionality and actively integrate 3D printing into the study of life sciences.”

In addition to running this project in his classroom, Lehrer has also released the hacking project in a Google file which walks you through the steps. You can earn this badge for completing this project, too, either as a group or an individual. It’s possible that I’m just going through a midlife crisis, but I’ve already figured out a pretty awesome animalized version that I’d like to make for myself.  I think with just the right design, I could finally catch my brother. Discuss in the Grab-Tor forum at 3DPB.com.