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Jan 21 16 5:44 PM

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While the Ada hand is capable of gripping a pen, it can't grip the pen firmly enough to write easily.

To find a way to enable the Ada hand to firmly grasp pens of varying sizes so that it can be used to write.

1. The solution must not impact on the normal operation of the hand
  • It must help with grasping pens but not prevent it grasping other objects
2. The solution must be 3D-Printable
  • ​As a minor improvement, the solution shouldn't change the manufacturing processes
3. The solution must be licensed under a Creative Commons Attribution-ShareAlike 4.0 International License
  • Since the original Ada hand is released under the this license, any derivatives must be distributed under the same  license.
To design a "notch" or "hole" inbetween the thumb and index finger which a pen could be fed through or could rest on and/or  be pinched by. This could provide enough stability to maintain a good grip on the back of the pen while the pinch grip held  the pen nearer the tip.
1. Design a small "Notch" feature to secure a pen between the thumb and index finger
2. It should be 3D printable
3. It shouldn't get in the way of any finger movement or grip patterns
4. It should guide the pen to the pinch point of the thumb and index finger where it would be held
5. It should be capable of holding pens of varying diameters, from handwriting pens to whiteboard markers 

1. Leverage the flexible property of the Ninjaflex to create a pinching effect on the pen shaft.
2. Prototype by printing a partial hand (just finger and thumb) to save time.
3. Work from the Ada design files in Blender.
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#2 [url]

Jun 19 16 9:47 PM

Holding pen

I have not experimented with the Ada hand yet but I will be very soon. As far as holding a pen can you not make adjustments with the thumb servo and the first fnger servo in order to gram the pen? I attached a video of  different hand I have completed showing writing with a pen just by making adjustments to the servos. It can grb a pen and write and still be able to grasp an egg without breaking it. I also attached link to photo holding egg as well. Please respond with feedback.


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Last Edited By: jbrawley Jun 19 16 9:50 PM. Edited 1 time.

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#4 [url]

Jun 22 16 3:20 PM

Hi jbrawley,

Nice Exii build! The thumb and first finger can get a pretty secure grip on the pen. However, there's still a little bit of wobble (which I think I can see your video too). It stems from the fact that most people rest the body of the pen against their first knuckle or in the crook of their thumb and this is what the notch was meant to emulate; the brief should have been clearer.

All the best,


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#6 [url]

Jun 24 16 12:59 PM

Exactly, it would hopefully be inconspicuous and provide a little bit of extra security.

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