Working on a new prosthetic arm

[2012_taco]

WOW, very interesting! I too was wondering how do you control the prosthetic hand. I realize it's electric but  how does it know when and how to move and grip etc? 

[moog5050]

Bionic

Taking the time to educate all of us on this is really neat.  I assume the sensors inside adjust grip based on your movement of muscle?  If you don't mind me asking, how is the prosthetic held in place?  Not knowing a thing about this, that would be my first concern.

[Bionic]

9 hours ago, Moho81 said:

What a cool thread Bionic. I had no idea there was so much technology involved. In this day and age it seems so obvious that there would be yet I was still surprised. I may have missed it but how do you control the arm and hand like open and close the hand?


Sent from my iPhone using Tapatalk

Glad you're enoying it.  That is why I felt this would be a change of pace for people to read, I am very experienced in this, but still learn, and hear about tech stuff that is still amazing to me.  It seems as if this tech field is just simple not talked about in the world.

As far as operation of the hand, and electronic wrist....

There are multiple variations of how to control myoepectric arms.  My specific arms are all controlled identically to each other.  If you look back on the last set of pics, the very bottom pic has that skeevy looking container-like socket...that is where my arm inserts with the previously mentioned liner.  The 2 little rectangular pads with the metal on them, is what i use to operate the entire arm on.  Those boxes are called "Electrodes".  Electrodes pick up your muscle movements, they know when you flex, they know the strength in how hard/soft you flexed, and it gets sent to a microprocessor, and other electronics within the arm, that translates to the hand, and electronic wrist,  just what its supposed to do.  I will try to explain which muscles I use.  Make a fist, then make a knocking on a door motion with your wrist, WITHOUT moving your arm, JUST your wrist move.....now watch the inside of that arm just below your INNER elbow(where bloods taken), and you can see a small area bulge each time you make you a knock motion.  That muscle, is the one I use to open the hand, AND rotate the wrist in a counter clock-wise rotation.  Yes, the SAME  muscle, performs BOTH.  This is where bluetooth tuning also comes into play with a laptop, to tune the arm/hand.  Thresholds are setup where,  to open the hand, that muscle is flexed UNDER a specific strength intensity, while the strength is slowly reached i believe its longer than a half second .  To operate the wrist with that same muscle, you would firmly flex the muscle OVER that muscle strength used to open hand, and you must reach that muscle strength UNDER somewhere in the range of a half second. Make sense?  To open the hand fully, or partially, etc,  you hold that flex under the hand opens to the desired openness.   Same for wrist, hold that muscle until the wrist is rotated to the desired rotation.  My current arm in pics will rotate either direction almost 360 degrees.  No wires connect the hand, so thats no why it does not fully rotate.  My work arm with the othand hand, the full black carbon fiber is an older wrist rotator that will rotate 360 degrees as long as you want it to lol.  To close the hand, or rotate wrist clockwise, you would do the SAME thing, BUT its a seperate muscle.  Make a fist again, but instead of making a door knocking motion, bend your wrist the opposite direction....as doing so, you can see a bulge on the outside hairy side of your arm, just near your elbow, that is the muscle I use to close hand, and rotate wrist clockwise. 

It is tough at first to coordinate your mind to keep these intensities, and speeds correct, to do what you WANT with the hand/wrist.  A LOT more people do NOT use an electronic wrist rotator, because it is too frustrating for some user's,  and not worth it to them.  I am the opposite,  I cannot stand not having an electronic wrist rotator.   Drives me NUTS.  

Now to change grip patterns(hand gestures), I "co-contract" the two previously described muscles.  I basically flex BOTH, at the same time firmly.  Then it will change the position of the thumb, to grip objects differently.   One you complete a grip, and are done, the hand will automatically enter a relaxed hand position, and in 3 seconds, you will hear a beep beep, like a watch, and it goes back into the original thumb position, that I set as default, again via bluetooth on the laptop.

Some users actually use the co-contract muscle flex to enter into a dedicated wrist rotation mode, rather than the thumb change like I do.  It simplifies it for people, and thats great,  but i find it extremely slow, and unnatural,  but to each his own.

This is all for this hand.  My next hand, that I will get it a whole other world.  I will describe all that once i have it.  This hand will have 14 different available hand gestures to use, but the hand can be programmed with I think 5 at once.  You would flex muscles in different patterns to enter different modes, to sum it up.

[Bionic]

1 hour ago, 2012_taco said:

WOW, very interesting! I too was wondering how do you control the prosthetic hand. I realize it's electric but  how does it know when and how to move and grip etc? 

Read above post, forgot to qoute you also.

[Bionic]

1 hour ago, moog5050 said:

Bionic

Taking the time to educate all of us on this is really neat.  I assume the sensors inside adjust grip based on your movement of muscle?  If you don't mind me asking, how is the prosthetic held in place?  Not knowing a thing about this, that would be my first concern.

Glad you are enjoying this as much as I am.  Read the 2 posts above, if you have not.

I am fine with any question, a silicone line rolls over my left arm, or "stump", cant stand that word but it is what it is.  Silicone liner rolls over my stump like a sock on foot.  The liner has windows cut out for the electrodes(muscle sensors), and a pin with teeth is integrated into the end of the liner, when you insert your stump into the prosthetic, the pin clicks inti a mechanism inside the prosthetic arm.  This liner is an exact fit, and must fit PERFECTLY.   Too loose,  and you can get air bubbles inside the liner, too tight, and you will turn purple at the end or your stump, like a hickey.  Also, too tight will fatigue your muscles to the point, you literally lose all strength of your muscles within the liner, temporarily until its removed.

[Bionic]

I should also mention that these muscle sites are specific to each person.  They takes tests that find sites on your skin that have the best muscle signal with least effort of the user, and you must be able to focus on that specific localized muscle site.  Flexing along with other areas, can result in wrong hand movements, and could drop things with the hand, etc.  You need to be able to hold said certain muscle for a few seconds or so at a time.  Not as simple as it sounds, some really struggle with it, especially if they lost their limb, i was born missing,  so I dont know any other muscles because this is how I learned.

[Moho81]

Glad you're enoying it.  That is why I felt this would be a change of pace for people to read, I am very experienced in this, but still learn, and hear about tech stuff that is still amazing to me.  It seems as if this tech field is just simple not talked about in the world.
As far as operation of the hand, and electronic wrist....
There are multiple variations of how to control myoepectric arms.  My specific arms are all controlled identically to each other.  If you look back on the last set of pics, the very bottom pic has that skeevy looking container-like socket...that is where my arm inserts with the previously mentioned liner.  The 2 little rectangular pads with the metal on them, is what i use to operate the entire arm on.  Those boxes are called "Electrodes".  Electrodes pick up your muscle movements, they know when you flex, they know the strength in how hard/soft you flexed, and it gets sent to a microprocessor, and other electronics within the arm, that translates to the hand, and electronic wrist,  just what its supposed to do.  I will try to explain which muscles I use.  Make a fist, then make a knocking on a door motion with your wrist, WITHOUT moving your arm, JUST your wrist move.....now watch the inside of that arm just below your INNER elbow(where bloods taken), and you can see a small area bulge each time you make you a knock motion.  That muscle, is the one I use to open the hand, AND rotate the wrist in a counter clock-wise rotation.  Yes, the SAME  muscle, performs BOTH.  This is where bluetooth tuning also comes into play with a laptop, to tune the arm/hand.  Thresholds are setup where,  to open the hand, that muscle is flexed UNDER a specific strength intensity, while the strength is slowly reached i believe its longer than a half second .  To operate the wrist with that same muscle, you would firmly flex the muscle OVER that muscle strength used to open hand, and you must reach that muscle strength UNDER somewhere in the range of a half second. Make sense?  To open the hand fully, or partially, etc,  you hold that flex under the hand opens to the desired openness.   Same for wrist, hold that muscle until the wrist is rotated to the desired rotation.  My current arm in pics will rotate either direction almost 360 degrees.  No wires connect the hand, so thats no why it does not fully rotate.  My work arm with the othand hand, the full black carbon fiber is an older wrist rotator that will rotate 360 degrees as long as you want it to lol.  To close the hand, or rotate wrist clockwise, you would do the SAME thing, BUT its a seperate muscle.  Make a fist again, but instead of making a door knocking motion, bend your wrist the opposite direction....as doing so, you can see a bulge on the outside hairy side of your arm, just near your elbow, that is the muscle I use to close hand, and rotate wrist clockwise. 
It is tough at first to coordinate your mind to keep these intensities, and speeds correct, to do what you WANT with the hand/wrist.  A LOT more people do NOT use an electronic wrist rotator, because it is too frustrating for some user's,  and not worth it to them.  I am the opposite,  I cannot stand not having an electronic wrist rotator.   Drives me NUTS.  
Now to change grip patterns(hand gestures), I "co-contract" the two previously described muscles.  I basically flex BOTH, at the same time firmly.  Then it will change the position of the thumb, to grip objects differently.   One you complete a grip, and are done, the hand will automatically enter a relaxed hand position, and in 3 seconds, you will hear a beep beep, like a watch, and it goes back into the original thumb position, that I set as default, again via bluetooth on the laptop.
Some users actually use the co-contract muscle flex to enter into a dedicated wrist rotation mode, rather than the thumb change like I do.  It simplifies it for people, and thats great,  but i find it extremely slow, and unnatural,  but to each his own.
This is all for this hand.  My next hand, that I will get it a whole other world.  I will describe all that once i have it.  This hand will have 14 different available hand gestures to use, but the hand can be programmed with I think 5 at once.  You would flex muscles in different patterns to enter different modes, to sum it up.

Wow. Thanks for taking the time to write that all up. I went through the hand motions as you where explaining them. I imagine that now for you it’s second nature to flex the correct muscles to move the prosthetic how you want but the learning curve at the time had to be hard and incredibly frustrating.


Sent from my iPhone using Tapatalk

[fasteddie]

Wow ! Some interesting and great information . Never thought about how much technology and work goes into the design of prosthetics . 

Any problem going through the detectors at the airport ? 

[dbHunterNY]

as i read through this i can't keep the image of Marvel's Winter Soldier coming to mind.

[Bionic]

10 hours ago, TreeGuy said:

No theme. Straight carbon fiber !

Sent from my XT1650 using Tapatalk
 

Carbon fiber is a thought, a lot of people use it, I like to be a bit different, but not sure yet.  My work arm is full black carbon fiber, but it was supposed to be silver black regular carbon fiber.

[Bionic]

4 hours ago, Robhuntandfish said:

do a camo dip - that would be cool! 

 

They have access to hydro dipping, it tends to chip from what I am under the impression of, and have seen.  If I go with anything with a smooth surface,  I can always get vinyl wrap for bow season in camo, and blaze orange for rifle, things like that.  I also want to start a youtube channel,  as I had mentioned in camera threads, so I could letter up the arm in the channel name.  I want to see if it can be built out of aluminum, like the tin man on wizard of oz

[Bionic]

37 minutes ago, Moho81 said:

Wow. Thanks for taking the time to write that all up. I went through the hand motions as you where explaining them. I imagine that now for you it’s second nature to flex the correct muscles to move the prosthetic how you want but the learning curve at the time had to be hard and incredibly frustrating.


Sent from my iPhone using Tapatalk

Not a problem at all, my pleasure!

It truly has become second nature,  it helps that I have been doing this for over 25 yrs.  All same 2 muscles.  My parents taught me at approximately 3 yrs old how to use the electrodes with muscles.  They said it was hours and hours trying to get me to focus lol

[Bionic]

39 minutes ago, fasteddie said:

Wow ! Some interesting and great information . Never thought about how much technology and work goes into the design of prosthetics . 

Any problem going through the detectors at the airport ? 

A lot of the tech is unseen, or unable to be appreciated by people who do not wear them.  My arm setup seems basically compared to other hands, but it is in the movements, the smoothness of the finger mpvements, etc.  I can move this hand so slowly, that you can hear the gears meshing basically.  Some hands cannot even process such slow signals to it, and will move in incriments, because it gets confused in a way.

Never been on a plane lol.  At concerts, or government builds, and such or stadiums, I make sure the arm is obvious.   I have had them verify with the handheld that its JUST the arm tripping the detectors. 

[Bionic]

12 hours ago, Jdubs said:

The technology blows me away.  Bionic, this almost reads like you should be beta testing the new stuff to see if the engineers can keep up with you!  Outstanding. 

True story! In 2007 I actually was chosen by my arm office to be a beta tester for Touch Bionics ILimb fully articulating hand.  Touch Bionics contacted my arm office asking if they had anyone in mind who would be willing to give honest input, and advice on their ILimb hand.  I was asked, and obviously happily agreed.  So we built an arm, the flesh tone arm in chainsaw pics...i broke that hand NUMEROUS times, I gave input, and common sense ideas for the way the hand was to be put together.  They mounted the individual fingers to a plastic palm, with tiny screws,  well the fingers would pull out of the palm bucket, it would pull the screws clear out of the little plastic threads...stupid.  i suggested metal, they said too heavy....i said it has to be, if you pick up, or pull say a fridge door open, all that stress is on those chinsey plastic threads,  so i suggested titanium....i was told too expensive.   Well about a year later when the next version was offered, sure enough titanium frame like i suggested.  Even the wires to the thumb were ridiculous,  they routed the wires so they would bunch up, every time the thumb was rotated, and after a while they would break at the solder joint.  I received 3 free ILimb hands from them from 2007-2010 ish.  They had me speak to people in Manhatten, Ohio, King of Prussia, PA, and locally.  They would send a lincoln town car to drive the girlfriend, and I, pay for dinners, and hotel rooms.  It was a blast, this is part of the forunate events I have been offered, that i refer to.

[Bionic]

32 minutes ago, dbHunterNY said:

as i read through this i can't keep the image of Marvel's Winter Soldier coming to mind.

I had to look up images of that lol

[dbHunterNY]

23 minutes ago, Bionic said:

I had to look up images of that lol

bionic super arm. same side. if you don't know the story behind the character it could be confusing. he's one of the good guys though.

[Bionic]

So I just got home from the prosthetic's office.  Sunday morning, I actually fell on the snow covered ice,  and landed directly on the fingers of the prosthetic.   I heard a loud snap, and now only the thumb moves.  I was assuming, I would be able to submit for repair, and also be approved to start the process of a new arm.  Well it is either or at this point.  My current arm is my favorite, and most comfortable, and most dependable that i have had.  It is also the more characteristic,  and just too much has gone into it to not utilize anymore.  Options at this point, is to either repair the broken hand, submit for a brand new replacement hand, or see if insurance will approve a full new arm.  I am long over due for a new arm as far as insurance guidelines go.  The issue is, I was told thos hand will easily cost $5k-$10k or more to repair.  The hand is over 5 yrs old, and that is a long life for a heavily daily used prosthetic.  I was considering new setup originally, so I could swap hands on the go.  The fancy painted arm, with the broken hand, can ONLY use THAT specific hand.   At this point, the broken hand was left with the prosthetist,  and will be shipped overseas to Germany for a repair price qoute.   

[Bionic]

Side note,  I hooked up to a Bebionic, I was not impressed, it felt flimsy, and awkward shaped, the thumb was a manual thumb for as how it moves side, to side.  Here are pics on my old work arm.

 

[Marion]

THAT ^^^^ is an awesome looking arm and hand

You Can't Beat My Meat!!!

[turkeyfeathers]

Again , we’re all impressed of your willingness to school us on this subject and you’re perseverance to overcome   And bar none you blow Luke Skywalker away  with your no holds barred attitude. I find this thread very informative and eye opening. Thank you again for a wonderful thread to follow. 

[Bionic]

9 hours ago, The Jerkman said:

THAT ^^^^ is an awesome looking arm and hand

You Can't Beat My Meat!!!
 

That is my work arm, I need that in order to use other TD's(Terminal Devices, which are the hands, and other electronic tools).  That arm is real carbon fiber, blacked out somehow.  Here is a photo of the same arm with the Greifer vice tool, I use, this pinches so hard, it hurts.   Great for heavy manual labor.  The pic with the gray clamp type vice.  The pics with the hand, is my old old hand from 2007.  This is actually the ILimb, I helped with beta testing that I briefly talked about.  Also, a photo of hands that are now for parts, they have seen better days.  They are ILimbs, but 3 versions of them.

 

 

[Marion]

That is my work arm, I need that in order to use other TD's(Terminal Devices, which are the hands, and other electronic tools).  That arm is real carbon fiber, blacked out somehow.  Here is a photo of the same arm with the Greifer vice tool, I use, this pinches so hard, it hurts.   Great for heavy manual labor.  The pic with the gray clamp type vice.  The pics with the hand, is my old old hand from 2007.  This is actually the ILimb, I helped with beta testing that I briefly talked about.  Also, a photo of hands that are now for parts, they have seen better days.  They are ILimbs, but 3 versions of them.
 
 

You ever try giving someone a titty twister with that clamp hand? I can totally see myself doing that to my brother all the time

You Can't Beat My Meat!!!

[Bionic]

9 hours ago, turkeyfeathers said:

Again , we’re all impressed of your willingness to school us on this subject and you’re perseverance to overcome   And bar none you blow Luke Skywalker away  with your no holds barred attitude. I find this thread very informative and eye opening. Thank you again for a wonderful thread to follow. 

I appreciate those words.  I really am glad its found interesting to you, and other members.  All the typing, and figuring out how to explain this stuff, is well worth it.  I find it extremely interesting, and fun, and if I had the opportunity for a hand transplant....no, thank you.  

No thanks needed, glad you are enjoying it.

[Bionic]

3 minutes ago, The Jerkman said:

You ever try giving someone a titty twister with that clamp hand? I can totally see myself doing that to my brother all the time

You Can't Beat My Meat!!!
 

Not necessarily, lol.  Although, I have hit people with it, my older cousin, was a real you know what, and he corned me at my Aunt's house  trying to impress one of his dirtbag friends.  I hit him so hard with the fake arm he cried, and ran inside.  Made himself look like a sissy in front of his friend, and some family.   He was the type where if you complimented somethimg of his, he would say "I know".

[Marion]

Not necessarily, lol.  Although, I have hit people with it, my older cousin, was a real you know what, and he corned me at my Aunt's house  trying to impress one of his dirtbag friends.  I hit him so hard with the fake arm he cried, and ran inside.  Made himself look like a sissy in front of his friend, and some family.   He was the type where if you complimented somethimg of his, he would say "I know".

Hahaha that's histerical and sounds well deserved. Bet he didn't try that again

You Can't Beat My Meat!!!