Design
v7 has six degrees of freedom plus a gripper. The wrist is RPR: a roll joint followed by a differential for pitch and roll. The segments are 2020 aluminium extrusion, and most other parts are 3D printed.
A NEMA 23 drives the shoulder, and NEMA 17s drive the base, elbow and wrist. The base, shoulder and elbow run closed loop. The joints use custom cycloidal drives I designed, and the 15:1 low-profile gearbox is published on MakerWorld.
Control and learning
An ESP32 runs a bridge so a ROS 2 master, such as a Raspberry Pi, can control the arm. I collect demonstrations with a leader arm built around AS5600 magnetic encoders, and used them to train a SmolVLA policy on about 30 episodes. The shakiness in the video comes from that small, fairly low-quality dataset.