Inspired by BostonDynamic and rationalized by youtuber James Bruton's openDog project (https://www.youtube.com/playlist?list=PLpwJoq86vov_PkA0bla0eiUTsCAPi_mZf).
Designed around Tower Hobby's 9g micro servos and super glued together frame. I set the servos to 90° then mounted the legs so each joint was perpendicular. The servos mount with their supplied screws and are interference fit into the joints, your servos may have a different horn fits so test before printing all connections.
(1) Arduino Nano (Headless)
(1) 16ch PWM driver
(12) Tower Hobby 9g servo
(2) Frame-Vertical Pivot
(6) Frame-Stiffener Vertical
(6) Frame-Stiffener Horizontal
(4) Shoulder Pivot
(2) Leg-Upper LH
(2) Leg-Upper RH
(2) Driver Support
(1) Nano Support
All Legs = 48mm
Shoulder to Shoulder Pivot = 40mm (Left to Right)
Shoulder to Shoulder Pivot = 80mm (Front to Back)
With 90° being centered and perpendicular when assembled:
Shoulder Pivot +/-17.5° (Left/Right)
Shoulder Pivot +40.0°/-46.5° (Front/Back)
Knee Pivot: +70°/-73° (Front/Back)
This is a work in-progress so when I have some code I will post it. It may be awhile because while working through this design I thought up another, slightly larger version I would like to post.