Afinia, SeeMeNCN, Ultimaker, Makerbot, Lulzbot, and
The actual cost of the materials to construct the hand
is about $50. That's practically free compared to the cost of
prosthetic devices that range in the tens of thousands of
The best part about this whole thing is that the low
cost makes this life-changing technology available to millions
of people that could never afford a commercial prosthetic.
One of the current hand designs — the Raptor — has four
fingers and a thumb. The closing action of the hand is
powered by bending the human wrist up to 30 degrees
with tension strings that cause the fingers to curl
in the same motion as a natural hand making a
fist. This can provide the user with enough force
to grip many objects, and it can support up to
20 lbs of weight. That's not bad, plus it doesn't
The basic Raptor hand has about 30 printed
components that actually snap together with pins
to hold all of the fingers and linkages together.
They are in a very nice design and could also be a
good starting point for non-organic critters, as
well. Of course, this is only one of the designs the
group is working on. They are also working on an
above elbow amputation model.
e-NABLE also makes it possible to contact the
group to discuss a custom design, so the specific
needs of a human patient can be met.
Recently, the e-NABLE group hosted an event
at the Johns Hopkins Hospital in Baltimore, MD.
Hundreds of medical professionals, patients,
families, and volunteers gathered to attend
lectures, classes, and watch videos that taught
them how to assemble over 200 of the Raptor
The plastic components were printed by
volunteers from all over the world. Along with
printers, time, skill, materials, and passion were
donated to this noble cause. Many of the folks were quite
touched by the emotions of the patients and the family
members that attended, and observed these devices
changing the lives of the users. One of the coolest things
about this group of designers and builders is they are not in
it for the money or notoriety. They just do it because it's a
good thing. Folks could learn a really good life lesson from
this event. I learned one, myself.
Since this is an open community, anyone can join
e-NABLE to share their expertise and experience. They are
always looking for folks that are CAD designers, builders,
dreamers, organizers, and/or assemblers. The e-NABLE
website is http://enablingthefuture.org/. It's full of
information, videos, and, of course, all of the open source
CAD files for the various hands.
Hmmm ... maybe today would be a good day to give
someone a hand. SV
68 SERVO 12.2014
Exploded view of the Raptor hand.
Attendees at the recent e-NABLE event hosted at
Johns Hopkins Hospital.