Tuesday, January 15, 2013

Animatronic Hand

I have a project coming up that I really want to make, but it requires some animatronics.  I have never made anything animatronic before, so before I get cracking on that project I better learn some animatronics!  So this blog entry is going to be about my first attempts at making an animatronic hand.

I did a web search on how to make an animatronic hand, and the best, simplest one I found was on Instructables.com (or click here).  That person made their hand out of some electrical tubing.  I decided instead of trying to find the tubing that I have somewhere in my house, that I would simply make it out of the abundant material I have laying around - namely crafting foam.

For this project I'll be using one sheet of thin foam (blue), and one sheet of thick foam (white).

Using a ruler and knife,  I cut the blue sheet into 1.75" strips, and cut a few .5" strips from the white foam. 

I also cut a few .25" strips from the blue foam.

Next I cut the 1.75" strips into 3" pieces.  These will make up the individual segments (or phalanges)  of the fingers.  I cut 4 for each finger (20 total).

Then I took one segment, looped it around, and glued it to make it cylindrical.

I repeated this for the remaining 19 segments.

When that was done I took some scissors and cut roughly a 45 degree cut off each end of 15 segments...

....and cut a 45 degree angle off only one end for 5 of the segments.  These 5 will be the finger tips.

A few minutes later and all segments were cut.

Next I took one of the .25" blue strips and glued a finger tip onto it.  I made sure that the widest part of the finger segment was glued to the strip.

When the glue dried I added the other segments.  I left enough room in between each segment to allow the finger to bend. 

Then I repeated this process for the other fingers.

When that was done I took the .5" thick white foam strip and glued the tip of it to the insides of the finger tip.  I made sure to adhere it to the inside wall farthest from the blue strip.

When the glue dried I pulled the rest of the white strip through the insides of the finger segments.

Now I could hold the bottom segment of the finger and pull the white 'tendon' to make the finger bend.

It didn't come out perfect though.  You can see some bunching happening at the top 2 'knuckles'.  But it will do for now.

I glued and added the white strips to the other fingers.

Then I cut a strip of thick white foam and glued it to the bottom segments of each finger.

And the glued another white piece and bent it around to make the thumb.

Then I glued the rest of the foam sheet to create the back of the hand.

And then bent it a little and fit it through a large PVC coupling.

And that is it for now!

I still need a little bit of practice with animatronics, but it wasn't a bad start.

All in all this project only took about an hour to make, but a lot of that had to do with the fact that this was made from 2 sheets of foam.

My second attempt will probably be made with a more durable material.

I invite anyone with or without know-how on animatronics to leave comments or ideas on how to make a better hand.  As soon as I get good at this I will use it towards that project I really want to work on - an animatronic Hellboy hand of Doom!

The next day I decided to try another one.  This one will be slightly larger which should hopefully make it a little easier to bend the fingers.  I will also be using the same foam materials as my initial hand was.

For this hand I decided to try making the puppeteering work, so I made some finger grips out of thick foam.

and I glued the grips to the ends of each 'tendon'.


The grips work well and the fingers now bend when my fingers do.  I still have to hold the foam hand steady with my other hand in order to puppeteer the foam fingers, but that's simply because I haven't built a foam wrist.  But I'll get there!

For my final practice animatronic hand I decided to use some plastic tubing I had hanging around.

Like the Instructables tutorial, I made cuts in the tubing where the finger would bend.

I then tied a piece of string to the fingertip...

and let the rest of the string travel through the inside of the finger.

When I pulled the string the finger easily bends.

I repeated this process for the other 4 fingers.

And then I glued a strip of cardboard behind each 'knuckle'.

Next I constructed a palm out of insulation foam to hold the fingers.  There is a hole on each side - one to hold the fingers and one to pull the strings from.

I then glued the fingers in place and let the string exit through the other hole.

Works like a charm.

Next I cut a hole for the thumb.

I then inserted the thumb and glued it in place.

I then glued another tube to the back hole and let the strings pass through it.

Next I crafted some fingertips out of insulation foam.

And then I inserted them and glued them into the hollowed fingers.

Then I cut some small rings from the tubing and glued them to the ends of the strings.  I labeled each ring so I know which finger each string goes to.

Here is a little video of how well the fingers move.

The biggest problem with this hand is that the strings keep getting tangled.  A simple solution is to make the bottom most finger segment very long - all the way to the wrist - and then making the rope and ring end at the opening to that elongated finger segment.

These exercises have given me enough know-how that I think I can begin making my animatronic Hellboy Right Hand of Doom!  This is going to be fun!
Thanks for reading!


  1. Wow, that is so ingenious! Have you seen Blind Squirrel's blog? He has a Hellboy hand tutorial you might find interesting.


    Like you, he is an ingenious and inspiring craftsman.

  2. Thank you Phil. You did show me Blind Squirrel's blog entry about Hellboy's hand - that is what has made me want to do this. I was originally going to make a static hand, like him, but as I rounded up all the material to make it I really wanted the fingers to move. That desire is what prompted this blog entry. So, thank you again and again!