When we decided to do a Otto Bot workshop in early 2017 I drafted the chassis pretty quickly. Although the legs are a bit complicated - the body basically is just a hinged box I already had - it quickly looked like a robot. But only with the workshop approaching got the last details fixed - e.g. the holders for the PCB, the "teeth" holding the head shut, the hole for the main switch, the final size of the ankle screws.

In parallel a group of people was working on a new firmware for the robot and a GUI for moving and calibrating the robot and to create new movement pattern. They currently still lack proper documentation and I have not yet decided whether to make them part of this project here or if they should get their own place - either here on HackaDay or may be just on GitHub.

As a result of this effort the chassis grew an additional mode switch that allows switching between different programs.

We also did building instructions in German with a lot of pictures.

With this in place we did two workshops with 5 kids each.

Lessons learned:

• Kids do not that the strength put the part together if they are cut very stiff - adults often do neither unless one uses tools like a vice or a mallet.

• Pressing the ankles onto the servos is hard and prone to damaging the servo gearing.

• Pressing on the legs is a bit better as they can get pulled on by a screw.

• Building the robot takes kids 3 1/2 hours + the soldering of the electronics which we did in fore hand for our second workshop.
• The legs are pretty complicated with several possibilities to put things together the wrong way.

Improvements to the chassis since:

• New driven ankle now uses a servo horn
• Simplified main switch position
• Simplified the legs a bit