Let's Make Robots!

PolyMorph Workshop 2 - How to make a Servo controlled Finger or Scorpion Tail

Grasps things
  • Sensors / input devices:

Introducing the PolyMorph finger ...... or toe if you dare to use as locomotion

The idea is Inspired from Anthropomorpic finger

PolyMorph is a Flexible plastic when thin and is actually quite durable.

NonStream Video link :-

How to Make Finger (circa 35meg)

Scorpion Tail in Action (circa 4meg)

 (1 CUN)


Extra Ideas :- ScorpionTail /Ocotopus Tentacle :- same idea but more joints.




LMR Qoute "Remember 2010 is the year of colours, smiling and sound for robots. (Chips on acid)"



Colourful Pictures for Fritzl & LMR Crews around the World.

 But so far i have been unable to make a sound like an Octopus or Scorpion.......


















Optional Extras :- 

For measuring tactile pressure a small black square "Thingy" is needed..

In my video example i am using it as a "joint" feedback monitor... 

......... you will have to watch the video to find out what it is ......

Very High Resistance at rest typically >10 Tera Ω 

and very Low Resistance when compressed typically <1 Ω

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that's an inspiration.  I am going to have to try that out.  Did you succeed in making an entire hand?

Gareth!! Amazing Scorpio tail!! Thank you for sharing this amazing technic!! 

I hope to have more spare time one of this days to try somthing like this!! ;-)

I am well impressed with the finger. (pat on the back for Gao,Claudia&Rose) , ( nice idea with errrrr im guessing Bicycle spoke :-)

Wow i to think i am driving it with a mear 55Ncm - (but it is metal geared)

 Yours will have quite a grip.

Here is some more detail on the finger tip - if you notice i have made an indentation to hide the knot,

coming to think of it the knot could be totally polymorphed in........

I have also posted some more profile pictures above for reference.

(I would love to see all of the fingers - good or bad hehe........)



I'll have to give it a try.  BTW, why not just use poly instead of fishing line.  I've supported a 3kg weight from a loop of poly cord about as thick as dental floss.  (When I supported it with only 1 strand, I could actually watch the long chains unravel as it stretched.  That's how I made poly thread.)
Because the leverage is not in favor of the servo you need fairly strong servos and thread to get any real grip. I plan on using 13Kg/cm servos with 32Kg line otherwise the hand is not strong enough to pick up a coffee mug.

The hand of Frankenstein (fingers made by several individuals :)

This is a work in progress, we will buy some fishing line tomorrow. Here's what we have so far:



Amazing........ full marks to you and your R&D Team...........

....... means i can sit back for a bit (highly unlikely).......

Maybe also buy some "thinish" bicycle cable (for gears) ....... this will "push" the finger straight (ie servo will be able to push and pull) 

We thought your video was that good that today I had Claudia, my assistant Rose and our mechanical engineer Gao as well as myself trying to make polymorph fingers. It is harder than it looks and our first attempts were somewhat less than impressive :D

We will try and make a complete hand using your instructions and drive it with a 13Kg/cm servo in an attempt to pick up an LMR coffee mug. 

Thanks again for the video, we have had lots of fun today. Here is a photo of Gao's solution to getting the finger straight and making the holes line up.


I have also thought about making a finger with many joints ie 10-15 segments ...... in an attempt to make a smoother round bend - ......... i will shortly have to buy more PolyMorph off you..........
A robot octopus perhaps?