Balance Walking Robot. 3d printed TYPE 1

I wanted to design the simplest mechanical version of a self balancing biped robot that could be 3d printed.

The build video can be found here.
https://youtu.be/ikx0GVau6-4

A short video of the robots operating will be found here .
https://youtu.be/JVck0YzVETA

And in Silk Copper PLA here.
https://youtu.be/yR-NXT7rPpw

On the gearmotor, be sure to use the slower verion 1/120 gearmotor. Then I also use a single 4001 silicon diode in the 3 volt supply line to reduce the motor voltage