A HANDMAKERS’ TALE

Wits en­gi­neers earn a high five

Sunday Times - - FRONT PAGE - By TANYA STEENKAMP

Pros­thetic hands that use brain sig­nals to con­trol move­ment sell for up to R150 000, but a team of en­gi­neer­ing stu­dents from the Univer­sity of Wit­wa­ter­srand have made a pro­to­type that will cost less than R2 000.

Armed with a 3-D printer, some sim­ple sen­sors and mo­tors, and a lot of brain power, six elec­tri­cal and in­for­ma­tion en­gi­neer­ing stu­dents have been work­ing on the ro­botic hand for three years. They hope that, once per­fected, it will be an op­tion for South Africans who can­not af­ford pros­the­ses.

“The prob­lem with the nor­mal pros­thetic hands is that they’re very ex­pen­sive and too cum­ber­some, too heavy or have lim­ited func­tion­al­ity,” said Ab­dul-Khaaliq Mo­hamed, a lec­turer and PhD can­di­date in the School of Elec­tri­cal and In­for­ma­tion En­gi­neer­ing at Wits, who is co-or­di­nat­ing the stu­dents.

“We’re try­ing to cre­ate a hand that’s rel­a­tively cheap but has suf­fi­cient func­tion­al­ity that al­lows users to do ba­sic daily move­ments. That’s why we’ve gone with the 3-D print­ing ap­proach and we’ve used very sim­ple sen­sors and mo­tors to re­duce the cost. That’s what is dif­fer­ent about this hand in re­la­tion to other hands.”

Charl Beukes, trustee of the Am­putee Club of South Africa, a non­profit or­gan­i­sa­tion that raises funds for those who can’t af­ford pros­thet­ics, said: “It’s es­ti­mated there are 2.1 mil­lion am­putees in South Africa based on the 2011 cen­sus, but we reckon there are a lot more. Around 80% don’t have any med­i­cal aids or funds to cover [pros­thet­ics].”

A rea­son for the high cost was that com­po­nents were made over­seas.

An­other is­sue was that pros­thetic arms sup­plied by the govern­ment were ba­sic mod­els that were so cum­ber­some and heavy that the per­son might choose to cope with­out it, Beukes said.

He said that in Gaut­eng more than 300 peo­ple had been wait­ing over two years for var­i­ous pros­thet­ics pro­ce­dures and in the Eastern Cape, the prov­ince with the big­gest bur­den, there was a wait­ing time of six to 10 years.

“We do see the bat­tles of peo­ple who can’t af­ford pros­thet­ics and many will never get it,” he said.

Mo­hamed said their pro­to­type hand was made from as­sem­bled plas­tic parts printed on a 3-D printer and weighed less than 1kg in­clud­ing all the mo­tors and elec­tron­ics.

“What it doesn’t have, which will be the heav­ier part, is the bat­tery. We’re still get­ting to that. But that could sit on the fore­arm, de­pend­ing on the level of am­pu­ta­tion.”

Mo­hamed’s re­search be­gan in 2008 and work on the pro­to­type hand in 2014.

“Nor­mally, with this kind of project, you’re look­ing at 10 to 20 years to get it func­tional and I’m not even sure that in­cludes the rig­or­ous med­i­cal test­ing that would be re­quired to get this into a com­mer­cial prod­uct. So we’re in for the long run.”

De­vel­op­ment is hap­pen­ing in stages. Last year the group per­fected a tri­pod pinch, which is used to hold a pen. The bi­cep and tri­cep are hooked up to the hand and as the per­son moves the mus­cles, the hand closes or opens. Sen­sors were then added to the fin- ger­tips to give the hand an abil­ity to sense force and how hard or soft to grasp.

“This year we are try­ing to in­te­grate the sen­sors to some sort of vi­bra­tion feed­back on the body. In­stead of you feed­ing the sen­sors into the brain, which will in­ter­pret some sort of sen­sory feed­back, we’ve got mo­tors that vi­brate, sim­i­lar to a cell­phone. We at­tach that to an­other part of the body and it will vi­brate and give you an in­di­ca­tion of how strong the hand is grasp­ing.”

Next on the list was an ex­oskele­ton for peo­ple who had suf­fered strokes or had a neu­ro­mus­cu­lar dis­eases.

“The ex­oskele­ton hand would be [used] to strengthen the hand of some­one who can’t re­ally use the hand prop­erly but has some sort of move­ment. We might start that next year, de­pend­ing on re­sources,” said Mo­hamed.

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