🤖 Quaddle

The World’s Simplest Quadruped Robot

Quaddle is a beginner-friendly, Wi-Fi-controlled quadruped robot powered by an ESP8266 or ESP32 microcontroller. Designed to be the "world's simplest" robot dog, it utilizes a 1-DOF (Degree of Freedom) design per leg, eliminating the need for complex inverse kinematics or heavy mathematics. Quaddle hosts its own built-in web interface and also includes an optional Android app, allowing you to control it seamlessly from any device.

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📑 Table of Contents

• Features
• Repository Structure
• Bill of Materials (BOM)
• Circuit & Wiring
• 3D Printing & Assembly
• Software Installation
• Usage & Control
• Interfaces

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🌟 Features

• Simple Hardware: Uses only 4 micro servos (SG90) and common, affordable components.
• Wi-Fi Control: Fully controlled via a lightweight, mobile-friendly web interface hosted directly on the ESP.
• Dedicated Android App: Includes a pre-built Android APK (Quaddle.apk) for dedicated smartphone control.
• No App Required: Works on any device with a modern web browser via its IP address.
• Easy Assembly: Fully 3D printable chassis with snap-in designs for the servos and components.
• Pre-programmed Animations: Includes actions like moving, turning, waving, sitting, and tail shaking!

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📂 Repository Structure

Quaddle/
├── QuaddleCode/        # Arduino source code (C++) for the ESP8266/ESP32.
├── Quaddle_STL/        # 3D models (STL files) and Blender source files for printing the robot.
├── QuaddleApp/         # Android application APK for controlling the robot.
├── codeDirectWifi_v1.ino/ # Alternative Wi-Fi code (Direct AP mode).
├── SchematicPro.png    # Circuit diagram for wiring components.
└── README.md           # Project documentation.

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📦 Bill of Materials (BOM)

Component	Description / Specification
Microcontroller	NodeMCU (ESP8266) or ESP32 Development Board
Actuators	4x SG90 Micro Servos
Power	3.7V LiPo Battery (18650 or similar)
Charging Module	TP4056 Module with Battery Protection
Voltage Regulation	5V Step-Up (Boost) Converter (for servos & ESP)
LEDs	2x LEDs (for Quaddle's "eyes")
Capacitor	1500µF or similar (placed on servo power line to smooth startup current spikes)
Switch	SPDT Slide Switch
Hardware	Jumper wires, small screws for servos

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🔌 Circuit & Wiring

Here is the general schematic representation to help you connect all the components correctly:

Pin Connections (Based on NodeMCU / ESP8266)

Component	ESP Pin	Notes
Front Left Servo	D1
Front Right Servo	D2
Back Left Servo	D3
Back Right Servo	D4
Left Eye LED	D7	Connect with appropriate current-limiting resistor.
Right Eye LED	D8	Connect with appropriate current-limiting resistor.

Note: Ensure the servos are powered directly from the 5V boost converter output, NOT from the ESP's 3.3V logic pins. Connect the common ground!

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🖨️ 3D Printing & Assembly

All necessary 3D models are located in the Quaddle_STL folder.

• You can print individual parts or use the provided all_in_one_quaddle STL files.
• Recommended Settings: 0.2mm layer height, 15-20% infill, PLA or PETG. No supports required for most parts.
• Check the original Blender (.blend) files included if you wish to modify the design.

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💻 Software Installation

1. Install the Arduino IDE.

2. Install the ESP8266 or ESP32 board manager in the Arduino IDE.

3. Open QuaddleCode/QuaddleCode.ino in the Arduino IDE.

4. Locate the Wi-Fi configuration section at the top of the code and update it with your network credentials:

   const char* ssid = "YOUR_WIFI_SSID";
   const char* password = "YOUR_WIFI_PASSWORD";

5. Connect your ESP board via USB.

6. Select the correct board (e.g., NodeMCU 1.0 (ESP-12E Module)) and COM port from the Tools menu.

7. Click Upload to compile and flash the firmware.

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🚀 Usage & Control

1. After a successful upload, open the Serial Monitor in the Arduino IDE.
2. Set the baud rate to 115200.
3. Press the RST (Reset) button on the ESP board.
4. Wait for it to connect to your Wi-Fi network. Once connected, it will display an IP Address (e.g., 192.168.4.1).
5. Ensure your phone or PC is connected to the same Wi-Fi network.
6. Open a web browser and navigate to the displayed IP address.
7. You will see the Quaddle control interface. Enjoy driving your robot!

(If the robot remains idle for 3 minutes, it will automatically play a "shake tail" animation!)

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📱 Interfaces

Web Dashboard

Control Quaddle directly from any browser! The web interface is lightweight and mobile-friendly:

Android App

If you prefer a native application, a pre-compiled Android App is provided.

• Navigate to the QuaddleApp directory.
• Download and install Quaddle.apk on your Android device.
• Open the app, configure it with your ESP's IP Address, and start controlling Quaddle!

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