I've been working on Hollies hand since the 3rd versions mechanism wasn't suitable. Here are some renders courtesy Blenders cycles render engine.
This version made a number of changes to the finger hinges to try and make them easier to move. I also removed tendon tubes from the inside the palm to reduce resistance to the tendons.
I also moved the thumb to an angle which would be more suitable for grasping. I also removed it's ability to move since it just added more resistance to the mechanism.
I moved the hinge to the palm to the back of the hand which again should help the tendons move.
The tendon anchors worked well so I kept them from the 3rd version. There are now only 4 tendons but 5 possible anchor. I could have removed one, but the tendon routing would have been more difficult and made it look unbalanced. Also +1 to redundancy.
Now I should be getting this on star wars day (may the 4th). It should take a day or so to add padding and tendons and then hopefully testing can begin.
Ok this is much more important than a new website look!
Deus Ex: Mankind Divided has been announced with a new trailer. I played the Original Deus Ex 14-15 years ago and it had a very formative experience on me. Deus Ex: Human Revolution added quite a large amount of fuel to the fire that drives my interest in prosthetics.
So I'm happy to announce the websites new look. The original design had hints of the 2000's about it and so I hope this new design brings it up to about the 2011-12 period.
On some other news the freelancing is picking up pace and so I should have more money to put into development work.
Now the photo of the website for social media linking and those on mobile etc etc.
Hey everyone. I have some big news about my current prosthetics project. I have gone and ordered the prosthetic hand from shapeways and it should be arriving in a weeks time. This has effectively been paid for by those who have bought from my shapeways shop, so thank you to all of you.
As you may be able to tell from the above renders I have finally learned how to use Blenders Cycles render engine!
Whilst the elastic elements don't yet neatly fit within the fingers this is due to the hand being quite small. As Hollie grows bigger they should disappear in later designs.
You may notice that the tendon torsioners are similar to James Holmes Siedle's design. This is because I re-engineered the idea for use in SLS nylon. I adjusted each block so they sat parallel with the back of the arm to maintain a sleek look. I also made two version of the rotary part of the tensioner.
I'll update the blog once I receive the hand. Hopefully it'll be ready for Hollie to start using.
Since I'm based in the UK it's always nice to see local stuff turn up. I also like seeing the digital descendants of my design from two years back.
I notice an interesting tensioner system by James Holmes Siedle. I'm reverse engineering it for Hollies hand since I wasn't happy with the screw version.
I was looking at my posts and realised I hadn't posted an update about hollies hand. This is about v3 of the hand which had some issues that would mean it wouldn't work. I've been doing some R&D on it and hope to have something coming together in the next few weeks. Unfortunately I have freelancing and consulting gigs to find that're distracting me.
I posted the design to thingiverse a while ago.
Here is a part of the version 4 hand, which involves fingers and hinges printed all as one piece.
For the last year I’ve been working at Hobs Reprographics as a 3D Printing technician. In this role I’ve mostly been taking peoples 3D files and converting them into a 3d printable format, as most programs can’t export suitable files on their own. I then printed them out in either a Projet 660 full colour printer or an ProX 800 SLA printer, and very occasionally a Cubex.
Anyway I learned a lot from Hobs, but as you may have noticed my blog posting had slowed down significantly. This echoed the slow development of what I was doing in meatspace. My main endeavour has been to make a prosthetic hand for Hollie. As I was only able to grab a few hours here or there, and was pretty tired even when I could, the progress was slow.
So I took the plunge again and have decided to set up as a freelance design and a 3D printing consulting expert. This should give me the flexibility to finish what I want to whilst providing an income.
So if you, or someone you know wants to design something for 3D printing then get in contact with me. Or if you’re with a company looking at getting into 3D printing but are not sure if you’d get the most out of it, or which of the hundreds of printers to buy, then again contact me.
I shall be setting up a dedicated website and twitter handle for the design and consulting job probably tomorrow. Pricing will also go on there. I’ll clean up this website and take advantage of some new shapeways apps. I’ll set up some permanent cross linking between my website, twitter facebook etc.
Some of you may now about Bioloids.
These are cute little humanoid robots designed for research and playing football, although there may be some other uses. Anyway I noticed that they lacked one thing… well ok two things…. in the form of hands. Yes you can put together some parts to make a gripper, but it’s a bit large and not as anthropomorphic as the rest of the bot. I decided to remedy this, and thanks to Trossen robotics putting the CAD parts online I got to playing around with it. It turned out to be surprisingly easy to design parts that would fit. Since I don’t have a Bioloid, or a spare servo I can’t really test this, but I might end up putting it on shapeways.
In other news I am still working on the full size prosthesis for Hollie, as well as the conventional robot hand. I’m just working on the kinks regarding the nylon printed springs. It’s proving to be very much a goldilocks thing, where no designs yet are just right.
One big issue is the hysteresis of the spring. It starts at position A, moved to position C, but doesn’t move back to A, but partway between them to B. Luckily movement between B and C is reliable and predictable. The problem is that if I print in position A I need to know that position B will be ok.
The following is an overview of how I went about about creating Hollies unique Robohand.
The first step involved Hollies father creating a series of alginate molds of both her left and right hands. Instructables gives a large number of tutorials on this process, with a number of them being focused on hands.
He then used these alginate molds to make plaster models of Hollies hands.
I then took these plaster models and used a technique called Photogammetry to turn these models into Computer models. The particular tools I used were 123d catch and Autodesk recap 360. These are both free Autodesk products that let you turn a number of photos into a 3D model.
I used a grey paint to bring out the contrast in the hand.
I also added coloured dots to the hand which gives myself and the software reference points to find in 3D space.
The final addition I made used a giant coloured QR code, which the model rests on. The QR code serves the purpose of helping the software know the surface is flat, as well as giving reference points to pick. The colour is also there to help me identify which precise square I’m using as an alignment mark. Trying to identify a black square out of many black squares is needlessly difficult.
The resulting model looks something like this:
Not very useful, so I used another free bit of software called Blender, to edit out the parts of the mesh I don’t need.
Blender gave me some useable models, but photogammetry isn’t perfect and so I used a somewhat less free piece of software called Zbrush to tidy things up further, as well as to re-position the fingers.
Quickly back to Blender to create a printable model,to scale things correctly and to mirror Hollies full hand. Then I printed out the first models on my Lulzbot printer. This gave me a direct comparison to the plaster cast hand to check.
I will describe how I combined the two models to create the fitting hand in Part 2