Most legged robot builds reach for hobby servos or expensive brushless actuators, so a dog built from scratch around low-cost gimbal motors is a refreshing starting point. The first milestone is a single leg with 2 DOF, and it already moves with real authority: it bends and extends fast enough to jump its test rig up and down the rails.
The test setup looks tidy. The leg sits on two vertical metal guide rails clamped to a desk, with grey 3D-printed linkages, housings and segments driven by integrated actuators. Wires run to breadboards, power lines and control boards beside a laptop showing the source code. Each actuator combines a planetary gearbox with a belt reduction for roughly 14:1, a mix used to keep the design compact. The motors themselves are 2805 140kv gimbal units.
The control stack is the part that impresses me most. A Raspberry Pi runs the gait-style movement and sends target commands to a master STM32 at 50Hz. That master connects to four slave STM32s, one per leg, each driving three motors with FOC at a 6kHz loop. For such a budget-friendly actuator choice, that is a serious amount of control engineering behind it.
Homing is sensorless at this stage: the legs fold to the home position, and the robot detects it by an increase in error rate. Once powered and homed, it always knows its target position, with slight backlash. Adding encoders to the other joints was rejected since that would raise design complexity, electronics and cost. The next step is a PCB to test all 12 motors, with the finished robot planned at 12 DOF and about 3kg. In the demo the leg also pushes against an open hand placed beneath the foot and retracts, and that push looks convincing to me.