I've been designing an actuator that is powerful enough for a full sized humanoid robot.  The goal is to get something that has huge torque, a parts cost of around $100, meets durability requirements, and is easy to build.  The early stages look promising (video), but I think that it will take a long time and many iterations to get it right ... which is why I'm starting now!  

Stumbled onto a design for a 3D printed Jansen Linkage on Thingiverse.  A Jansen linkage is a mechanical linkage system for creating a complex gait that is actuated by a single servo. To create a full walking robot 3 leg pairs are needed.  I was intrigued and tried to print out several Thingiverse designs but couldn't get anything that was low enough friction to actually be functional.  The Thingiverse designs were also lacking a servo harness and instructions.  I created a new design that uses radial bearings and a MG996R servo that looks very promising (see the video).  Unfortunately I ran out of bearings, so I couldn't finish the robot (more bearing on order now).  I might post the parts if anyone is interested.  Could be fun to try and design a mechanical linkage for some portion of a bipedal leg.  Check out the TED talk that Theo Jansen gave where he shows off his beach walking robots ... interesting for the walking mechanism and simple mechanical "intelligence".  Also found an interesting site that compares the Jensen linkage with a Klann linkage.

I've been experimenting with a new version of the Strain Wave Drive (same idea as a harmonic drive but not made by the Harmonic drive company). It is fully functional and includes a dynamic spline for the output rather than the stabilizer and cup style flex spline as in the previous prototype.  This version still uses bbs for the bearings, which is probably a weak point in the design but keeps the cost of the drive below $5.  The double ring bearings on the dynamic spline help to stabilize the output of the drive and reduce any off axis wobble.   Video of the new strain wave drive in action.

A big thanks to Andy for designing a custom electronics board for FOBO!  This combines the parts from the Arudino Uno and the servo shield into one inexpensive board.  He went above and beyond by also creating a great tutorial on how to make the board and assemble the components.  This will be really helpful to everyone who hasn't been able to get a hold of the discontinued servo shield used in FOBO.  Really great work!  

Made a 1/3 scale model of ROFI. It has all of the same parts as ROFI, but the electronics and servos are all printed (i.e. the robot isn't going to be moving by itself without a lot of imagination ;-). I originally created it because I just got a Replicator 2 and wanted to see what the new printer was capable of. After the model was printed and sitting on my desk two things occurred to me :

1. Working at 1/3 scale would be really useful for prototyping future robots.

2. Because it was so fast and cheap (3 hours to print and $2 in parts) it might be a good "gateway drug" to get more people to try building robots. After all, I never really thought I could build robots until I downloaded the parts and built a modified Z stage for my Cupcake printer.