Stanford Quadruped Explanation

This repository contains the software that makes Stanford Pupper and Stanford Woofer work—small, four-legged robots built around a Raspberry Pi that can walk, trot, and jump. If you've ever wanted a robot dog you could actually build yourself, this is the code that brings it to life.

The robot is controlled through a PS4 game controller connected over Bluetooth. When you move the joystick, the signal travels to the Raspberry Pi, which runs the main control program. That program decides how the robot should move—whether it's trotting (diagonal legs moving together), walking, or standing still. Then it calculates exactly what angle each of the robot's motor joints needs to be at to achieve that movement, and sends electrical signals to the motors to move them into position. All of this happens in a continuous loop, many times per second, so the robot responds smoothly to your controller input.

The clever part is how the robot figures out which legs should be pushing and which should be stepping forward at any given moment. The code has a "gait scheduler" that choreographs the legs—like a conductor directing an orchestra—deciding when each leg pushes backward against the ground and when it swings forward to take the next step. The "stance controller" handles the legs that are on the ground, pushing them backward to move the body forward (and rotating them if you want to turn). The "swing controller" picks up the legs that just finished pushing and swings them forward to the right position for the next step. Finally, something called "inverse kinematics" translates all these positions into the specific motor angles the robot needs.

You'd use this code if you want to build a Stanford Pupper or Woofer yourself—the project includes a full bill of materials, assembly guide, and installation instructions. It's designed for robotics enthusiasts, students, and makers who want a hands-on project that produces something genuinely cool. The code is open-source, so you can also modify how the robot walks, add new gaits, or experiment with different control strategies.