Search found 32 matches

by AdamArabian
Mon Jun 29, 2015 4:16 pm
Forum: Hands
Topic: Cost/Benefit of thermoform palms
Replies: 6
Views: 1361

Re: Cost/Benefit of thermoform palms

Yes but you lose the precise tactile feel. You feel only pressre, not shape. Imagine holding a six sided die. You lose the sense of it's size and shape. You also can't feel if or when it starts to slip so you can't adapt your grip. There is also a lack of compliance (the soft tissue of your hand wra...
by AdamArabian
Sat Jun 27, 2015 12:08 am
Forum: Beta Testing
Topic: The Phoenix Hand (previously Eagle Hand) fabrication and mechanical function testing
Replies: 165
Views: 30520

Re: The Phoenix Hand (previously Eagle Hand) fabrication and mechanical function testing

John I like the simplification of the whippletree. I don't see a "results" report - did it work?
by AdamArabian
Sat Jun 27, 2015 12:05 am
Forum: Hands
Topic: Cost/Benefit of thermoform palms
Replies: 6
Views: 1361

Cost/Benefit of thermoform palms

I'd like to open a chat on the thermoform palms. I'm in the "anti" group (which I'm not sure is a group since I may be the only member...) as I feel that it would remove the proprioception that the user gains from the existing palm. The velcro diffuses it a lot but its I'm sure better than...
by AdamArabian
Tue Jun 23, 2015 7:26 pm
Forum: Beta Testing
Topic: The Phoenix Hand (previously Eagle Hand) fabrication and mechanical function testing
Replies: 165
Views: 30520

Re: The Phoenix Hand (previously Eagle Hand) fabrication and mechanical function testing

Jason - Just to clarify on Justin's point on the finger length, the big thing for us is field maintainability. We are focused on developing world communities so an ongoing relationship and proximity to repair parts cannot be assumed. It may make our needs too "special case" but our thought...
by AdamArabian
Tue Jun 23, 2015 7:19 pm
Forum: Myoelectric
Topic: MYOWare sensors - how to obtain?
Replies: 2
Views: 1273

MYOWare sensors - how to obtain?

I was looking at the MYOWare sensors kickstarter page (which I had apparently overlooked- I thought they were already for sale somehow) and saw that through the kickstarter a number of their EMG sensors were going to be provided to "eNABLE and limbitless". For the myo work we're doing over...
by AdamArabian
Mon Jun 22, 2015 5:38 am
Forum: Myoelectric
Topic: Limbitless Arm Finger Movement Potential
Replies: 2
Views: 1346

Re: Limbitless Arm Finger Movement Potential

Richard, I think its a bit muddier than that. COULD you make a hand that had fully articulated fingers, yes, but you would likely have to do it with sacrifice on other metrics; either cost, size, power efficiency, or some combination thereof. If you look at the JHUAPL MPL or DEKA Luke Arm you will s...
by AdamArabian
Wed Jun 17, 2015 6:33 am
Forum: Beta Testing
Topic: The Phoenix Hand (previously Eagle Hand) fabrication and mechanical function testing
Replies: 165
Views: 30520

Re: The Phoenix Hand (previously Eagle Hand) fabrication and mechanical function testing

Just a vote of support Jason for the work you're doing on this hand - I really like its key elements. Great job mobilizing support for the test builds; something we were never able to do!

Keep on keepin' on!
by AdamArabian
Wed Jun 17, 2015 6:30 am
Forum: Arms
Topic: Bloom Socket: First Prototype, Design and Usage Feedback Requested
Replies: 6
Views: 1712

Re: Bloom Socket: First Prototype, Design and Usage Feedback Requested

Skip - whats the ETA on the arm? We're pretty eager to see the latest!
by AdamArabian
Wed Jun 17, 2015 6:28 am
Forum: Hands
Topic: Avoiding fatigue from flexion
Replies: 6
Views: 1546

Re: Avoiding fatigue from flexion

You, my friend, have hit upon one of our holy grails. A voluntary open hand would be excellent but it would demand an enormous amount of strength in the forearm muscles in order to have any reasonable grip strength. Locking mechanisms have been tried (if you search on the google+ group you will find...
by AdamArabian
Wed Jun 10, 2015 4:41 pm
Forum: Beta Testing
Topic: The Phoenix Hand (previously Eagle Hand) fabrication and mechanical function testing
Replies: 165
Views: 30520

Re: The New Hand (previously Eagle Hand) fabrication and mechanical function testing

Jason, can you either point me to the original link or summarize key points of innovation on the new hand?
by AdamArabian
Mon Jun 01, 2015 8:44 pm
Forum: Arms
Topic: Bloom Socket: First Prototype, Design and Usage Feedback Requested
Replies: 6
Views: 1712

Re: Bloom Socket: First Prototype, Design and Usage Feedback Requested

I have a hard time determining what may happen - its such a nonstandard socket design that I don't know if any of us really have a sense for what a three-leaf design like that would do. It could be awesome, but it could also produce pinch points or abrasions at the edges. If you wore a sock undernea...
by AdamArabian
Tue May 05, 2015 1:31 pm
Forum: Hands
Topic: Falcon Hand
Replies: 23
Views: 3862

Re: Falcon Hand

Correct. The lever arm (distance between the tendon and the hinge pin) is what causes the movement so be reducing that distance you reduce the torque and thus delay operation of that joint with respect to the other. We were actually working with two joints in the finger so made that change progressi...
by AdamArabian
Wed Apr 29, 2015 5:08 am
Forum: Hands
Topic: Rubber Band Raptor Reloaded
Replies: 17
Views: 4694

Re: Rubber Band Raptor Reloaded

As a side note, we are also trying out the bowden cable designs advocated by (I think) Peter Binkley. I like the dental elastics a lot but for the folks in the middle east we are primarily designing for aesthetics are key.
by AdamArabian
Mon Apr 27, 2015 10:55 pm
Forum: Hands
Topic: Falcon Hand
Replies: 23
Views: 3862

Re: Falcon Hand

Oh ok. There are two crimp designs floating around I assume you've seen - one is ours on the falcon hand, the second is... er... I don't recall who had it but it had sort of a gear tooth design.
by AdamArabian
Mon Apr 27, 2015 8:43 pm
Forum: Hands
Topic: Falcon Hand
Replies: 23
Views: 3862

Re: Falcon Hand

Crimps for the whippletree? That would be awesome! I don't know that ours would work well (actually, I don't know that they wouldn't either) but the form factor has to be so small I'm not sure how to do it well!
by AdamArabian
Sun Apr 26, 2015 9:33 pm
Forum: Hands
Topic: Rubber Band Raptor Reloaded
Replies: 17
Views: 4694

Re: Rubber Band Raptor Reloaded

The ones we designed the falcon hand to were 3/8" but since you guys are redesigning around the raptor fingers it can be any length really so long as you get the separation right. In general you just want the separation to be juuuuust a bit greater than the neutral length of the rubber band. 3/...
by AdamArabian
Wed Apr 15, 2015 2:18 am
Forum: Hands
Topic: Falcon Hand
Replies: 23
Views: 3862

Re: Falcon Hand

You should try Autodesk Fusion. Its remarkably powerful and free for makers/inventors/hacker types. Andreas Bastian posted some excellent tutorials on how to use it for the eNABLE community. I can link them if you can't find them. I think they're on youtube.
by AdamArabian
Tue Apr 14, 2015 5:17 pm
Forum: Hands
Topic: Falcon Hand
Replies: 23
Views: 3862

Re: Falcon Hand

Oh absolutely - the design is fully parametric in solidworks but prior to transitioning it to public use it would need to have some intelligent scaling; I'm not sure how openscad works as far as converting the files over but we have some brute force ideas of how to scale things if its not easily con...
by AdamArabian
Sun Apr 12, 2015 3:48 pm
Forum: Hands
Topic: Falcon Hand
Replies: 23
Views: 3862

Re: Falcon Hand

I have, and I really like it for a transradial prosthesis. I don't think its a good solution for partial hands though since it requires bulking up the geometry. All the feedback I have (which again, is all international) is that overall our hands are too big, so adding a whippletree box just makes i...
by AdamArabian
Sun Apr 12, 2015 3:52 am
Forum: Hands
Topic: Falcon Hand
Replies: 23
Views: 3862

Re: Falcon Hand

We thought about that but I didn't think I could cut them close enough to the finger. I wouldnt want to leave sharp edges hanging out to grab on fabric or scratch someone.

The filament seems to work pretty well though.
by AdamArabian
Sun Apr 12, 2015 1:55 am
Forum: Hands
Topic: Falcon Hand
Replies: 23
Views: 3862

Re: Falcon Hand

I like your ideas for the band posts - we want to come up with a way to hide them away a bit if we can but we're working on some pop-off covers too which should work regardless (perhaps even a bit better as they would have more engagement surfaces) As for the palm, I'd suggest just running a palm wi...
by AdamArabian
Sat Apr 11, 2015 7:04 pm
Forum: Hands
Topic: Falcon Hand
Replies: 23
Views: 3862

Re: Falcon Hand

Jason, We've printed it on an expensive machine (uprint SE) and a cheap one (printrbot). Some tips: The fingers should be printed on their side, if necessary with internal supports (I get about 50% success without). Sorry if thats not in the instructions. I have to use a pick to clean them out which...
by AdamArabian
Sat Apr 11, 2015 2:47 pm
Forum: Hands
Topic: Proximals and elastic
Replies: 7
Views: 2513

Re: Proximals and elastic

New thread created... Feel free to comment on where we're going.
by AdamArabian
Sat Apr 11, 2015 2:43 pm
Forum: Hands
Topic: Falcon Hand
Replies: 23
Views: 3862

Falcon Hand

Jason suggested we start up a dedicated thread for the falcon hand work we're doing. hero-falcon-handa.jpg Quick summary: The falcon hand is a test bed we built at Seattle Pacific University. Problems we wanted to (and did) solve: 1. Maintainability - we want the design to be repairable by a one-han...
by AdamArabian
Fri Apr 10, 2015 3:23 am
Forum: Hands
Topic: Proximals and elastic
Replies: 7
Views: 2513

Re: Proximals and elastic

Sorry folks - been lazy about keeping engaged here but the falcon hand dental elastics work really well. I think they're great for field maintainability and long term support. The falcon hand was on haiatus for the last few months but we're driving it home over the next 10 weeks and will hopefully b...
by AdamArabian
Fri Mar 27, 2015 6:16 am
Forum: Hands
Topic: Design Goals and Processes
Replies: 7
Views: 1187

Re: Design Goals and Processes

I'd suggest removing "where possible" for both anthropomorphic geometry and leanness. I think these are just as critical as the other factors and shouldn't be sacrificed. The rest of the list is a dream sheet and those should be too. I'd also add however: -Ability to easily modify basic de...
by AdamArabian
Tue Feb 17, 2015 5:49 pm
Forum: General R&D
Topic: Reverse the pulley and tensioners?
Replies: 3
Views: 889

Re: Reverse the pulley and tensioners?

Indeed - and there has been a lot of dicussion on it and we really want to move forward on it. The challenge is that it means there is a force always trying to close the hand which must be overcome with wrist action. Thus if you want to be able to hold a five pound weight, you need to be able to ext...
by AdamArabian
Tue Feb 17, 2015 5:47 pm
Forum: Arms
Topic: Establishing safety guidelines and contraindications, topics to consider
Replies: 2
Views: 830

Re: Establishing safety guidelines and contraindications, topics to consider

Great list - on the one hand we have a need and opportunity to really help the community and make these devices better. However, as we formalize we need to recognize that we are also taking more and more ownership and responsibility for successes AND failures AND potential injury so this is not some...
by AdamArabian
Tue Feb 17, 2015 5:46 pm
Forum: Hands
Topic: Bracer; Gauntlet; Sleeve; Cuff; Bracelet
Replies: 11
Views: 2711

Re: Bracer; Gauntlet; Sleeve; Cuff; Bracelet

I don't think its too literal - there are things with these names already (from armory) so if we try to change them it is inherently incorrect.

HOWEVER - bracer is not in the normal parlance so I have no qualms going with what is most accepted.
by AdamArabian
Tue Feb 17, 2015 5:44 pm
Forum: Hands
Topic: Fill when printing
Replies: 12
Views: 2104

Re: Fill when printing

It depends significantly on how well your printer is printing, but in general the number of outer shells is much more important than the infill percentage. I've seen good prints anywhere from 25% infill up to 100% and just based on the engineering stresses it won't make much difference - your big pa...
by AdamArabian
Mon Feb 16, 2015 2:08 am
Forum: General R&D
Topic: Cabling: Strings and Things
Replies: 4
Views: 1064

Re: Cabling: Strings and Things

I concur on the <100lb line, though for a different reason - I didn't see significant stretch (I saw lots of compliance in the hands, but not a lot of line stretch) but significant bend resistance; this is a nonissue for dyneema and curtain cord since its highly pliable, and a nonissue for the very ...
by AdamArabian
Mon Feb 16, 2015 2:06 am
Forum: Hands
Topic: Bracer; Gauntlet; Sleeve; Cuff; Bracelet
Replies: 11
Views: 2711

Re: Bracer; Gauntlet; Sleeve; Cuff; Bracelet

I am in favor of this clarification in terminology. Perhaps we could use one of the exploded view drawings of the raptor to label parts so we are all able to talk common terms?

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