ESP32 Self-Balancing Quadruped Robot With ROS 2 Wireless Control and 3D GUI

This DIY quadruped robot uses an ESP32, micro-ROS, and ROS2 for advanced self-balancing with PID control, smooth walking gaits, and obstacle distance sensing via ultrasonic. It includes a stunning cyberpunk-themed GUI with real-time 3D orientation visualization, roll/pitch plots, PID tuning, and manual/keyboard controls. Perfect for robotics enthusiasts!

Capabilities:

1. Auto-balances on uneven surfaces using MPU6050 IMU
2. Walks forward/backward/left/right with adjustable speed and gait
3. Publishes distance data from HC-SR04 (ready for future obstacle avoidance)
4. Cyberpunk GUI with neon styling and 3D robot attitude cube
5. Keyboard or button control, per-leg overrides, sensor calibration

Materials

1. ESP32 development board
2. PCA9685 16-channel PWM servo driver
3. 8 × MG90S or similar metal gear servos (180° range)
4. MPU6050 IMU module
5. HC-SR04 ultrasonic sensor
6. 3D-printed quadruped frame (4 legs, 2 servos per leg)
7. 5–6V power supply/battery for servos (separate from ESP32)
8. Jumper wires, breadboard or PCB
9. Computer running Ubuntu 22.04 (for ROS2)

Slicing Settings (Cura, PrusaSlicer, or similar)

1. Layer Height: 0.2 mm (0.15 mm for smoother joints)
2. Infill: 25–40% (Gyroid or Grid)
3. Walls: 3–4 (1.2–1.6 mm thickness)
4. Supports: Tree supports where required (overhangs on legs/mounts)
5. Adhesion: 8–10 mm brim
6. Temperatures: Nozzle 200–210°C, Bed 60°C
7. Orientation: Body flat on bed; legs positioned to minimize supports

Printing Sequence

1. Print the body first (monitor initial layers).
2. Print the Top.
3. Print upper legs.
4. Print lower legs.

Post-Processing

1. Carefully remove supports with pliers or cutters.
2. Sand joints (220–400 grit) for smooth servo fit.
3. Test-fit servos (no screws initially); ream holes if needed.
4. Assemble using servo horns and screws (no glue required for joints).

The frame is now ready for electronics integration.

1. Attach hip servos to the body (one per leg corner).
2. Connect knee servos to the lower leg parts.
3. Mount legs to hips — ensure symmetric layout (front-right, front-left, rear-right, rear-left).
4. Secure the ESP32, PCA9685, MPU6050 (centered), and HC-SR04 (front-facing) on the body.
5. Test servo fit — horns should allow full leg movement without binding.

Wire the Electronics

1. Connect PCA9685 to ESP32 default I2C (SDA=21, SCL=22).
2. Wire all 8 servos to PCA9685 channels 0–7.
3. MPU6050 to secondary pins: SDA=32, SCL=33.
4. HC-SR04: Trig=25, Echo=26.
5. Power servos separately (common ground with ESP32).

Example wiring:

1. Install PlatformIO (VS Code extension).
2. Clone the repo:

1. Open the project, edit main.cpp: update WiFi SSID/password and agent IP (your PC's IP).
2. Upload to ESP32. LED should light up when connected.

Install ROS2 and Dependencies

On Ubuntu 22.04:

Setup and Run micro-ROS Agent

1. Install micro-ROS agent (use Docker for ease):

(Or build from source if needed.)

Run the Controller and GUI

In separate terminals (source ROS2 each time: source /opt/ros/humble/setup.bash):

Terminal 1 (Controller):

Terminal 2 (Main GUI — recommended):

Optional: Standalone IMU visualizer

GUI example :

Calibrate and Test

1. Place robot on flat surface.
2. In GUI, click "CALIBRATE SENSORS".
3. Use stance buttons to stand up.
4. Tune PID (start low Kp ~0.2) while gently tilting.
5. Enable walking — use WASD/arrows or buttons!

Enjoy your SpiderBot — it balances, walks, and looks futuristic! Share improvements on GitHub, Instructables .