News Robot Arm

DaisyDriver 2.0

The Sixi 3 robot arm is the result of many years of study and research. I’m trying to build my dream machine that avoids every problem discovered in my previous robot arms. My short list of desirable things include:

  • Easy manufacturing = use less unique parts = use repeating components.
  • Easy maintenance = daisy chain components.
  • Safer = no loose wires, always know where the arm is, responsive behaviour. (safety third!)

To that end I’m on my second attempt to design and program the board of my needs. Here’s where I’m at today, December 31, 2022. Read on for all the details.


The missing Spot Micro PCB is here!

So you built a Spot Micro (or you want to) and – because you’re very clever – you read the instructions first. You probably noticed there’s a section where you have to build a PCB from scratch. For a lot of people, that’s beyond their skill level …for now. In the meantime, nothing should hold you back from building a sweet walking robot dog, amiright? Cool.

Here’s a board we used in the past for a stewart platform, which are a type of robot you can read about elsewhere on this site. It’s a good start for driving a robot dog. ELEC-0132 stewart platform board was designed for 11 PWM signals out and 6 analog values in. I’m betting that one of them can be used as an extra out signal to drive all 12 motors in the Spot Micro’s legs.

The boards are made by OSHPark and you can get them here:

But maybe wait until I test this theory. If I do this post will be updated with a part 2 right here:

Robot Arm

Sixi Robot developments 2019-07-16

New OSHPark PCBs arrived

With this we can finally finish the hardware preparation for shipping units, after which we can also get a final bill of materials and start to package DIY kits.  There will be two flavors:

  • DIY kits with all the non-printable parts.
  • DIY kits with everything, including the printed parts.

Collision detection

The software only lets each joint of the robot move within a safe range to prevent wire twisting or other potential damage.  That piece of code does not consider the angle of joint A in relation to the value of some other joint B.  So it was still possible to make the arm hit itself.

This new collision detection code prevents each bone of the arm from colliding with other bones of the arm.  At present it is a crude collision detection system, using only the box around each joint.

Also now that these boxes have been calculated, the center of each box is known.  the mass of each bone can be pulled from the Fusion360 model, and then a point-mass physics model can be created to simulate forces like gravity.  This gets us closer to dynamics like push-to-teach and telling the arm “please push on this item with a force of N newtons”


Next we’ll be assembling the new shoulder design with the PCBs that should allow us to unplug the umbilical from the arm and the control box.  I’m thinking Twitch stream?  Maybe just a Youtube Live, given the recent Amazon protests.  Choice of evil companies… hmm…