So I have been working a huge amount on designing the arms.  I needed to make sure I get all of the articulation required but retaining some semblance of the human form factor. I decided I was not going to be able to have a five fingers but will have to go with two fingers and a thumb. My local print shop ran out of 3mm White PLA so I had to continue printing in 'natural' which I don't like as much, but never mind. Let me know if you can't see the video below, I forgot I had music on for this one so it is copywrited.

       The arm has a Yaw in both the upper arm and the lower arm. I had to design a new planetary gear for the lower arm yaw. I like it so much I will  probably redesign the upper arm to use this same yaw mechanism. I spent a lot of time debating whether I need a wrist 'pitch' and I have ultimately decided that I do need it as it is key to being able to pick things up and do other tasks in a human-like manner. So I now have a decent idea of how the hand will work and look but just need to design it. The hand is going to be designed to be strong enough to handle every day objects. I think if it can't crush a beer can, then it is not strong enough. Ultimately I want it to be able to pick up things like a drill or a shopping bag etc. It does look quite simplistic in design, but an incredible amount of thought has gone into the design to make this work.

The fingers and wrist pitch will be 'cable pulled' like many other designs out there and I am planning to have one motor in the hand to pull the thumb inwards to the centre of the hand for grabbing. So the thumb will have two actuators to enable it to do what the human thumb does by either opposing  the fingers to pinch or keeping the thumb flat and making a kind of fist shape.