ESP32 RC Car

A browser-based RC car project powered by ESP32-C3, featuring real-time control through an intuitive web interface with virtual joystick controls. Available in both single-board and dual-board configurations.

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Features

Core Features

• Dual operation modes: Default (2-wheel) and Omni (4-wheel) drive
• Mode switching via hardware switch
• Browser-based control interface with virtual joystick
• Real-time motor control and status monitoring
• ESP-NOW communication for reliable control
• Emergency stop function
• Individual wheel speed tuning

Communication Options

• Single-board WiFi mode
  • Direct WiFi AP connection
  • Browser-based control
  • Low latency for close range
• Dual-board ESP-NOW mode
  • Extended range (100m+)
  • More reliable connection
  • No WiFi network required
  • Split control/drive functionality

Setup Guide

Option 1: Single ESP32 Setup (Simpler)

1. Choose your desired mode and flash the corresponding code:
   • For Default mode: Flash default/default.ino
   • For Omni mode: Flash omni/omni.ino
2. Wire motors according to pin configuration
3. Power up the system
4. Connect to WiFi AP "Web RC Car"
5. Navigate to 192.168.1.101 in browser

Option 2: Dual ESP32 Setup (Advanced)

Requires two ESP32 boards - one for control, one for the car.

Controller Options:

A. Basic Controller:

• Flash control.ino to controller ESP32
• Simple setup, fixed control mode

B. Advanced Controller (with mode switching):

• Flash master_control.ino to controller ESP32
• Requires additional wiring:
  • Mode switch to PIN 5
  • OLED display (SDA: 3, SCL: 4)
• Allows real-time mode switching

Car Setup (Required for both controller options):

1. Flash drive.ino to car's ESP32
2. Wire motors according to pin config
3. Configure MAC addresses:
   • Set receiving MAC in drive board
   • Set corresponding MAC in controller

Usage:

1. Power up both boards
2. Connect to controller's WiFi:
   • Basic: "Web RC Car"
   • Advanced: "RC Default Mode" or "RC Omni Mode"
3. Navigate to 192.168.1.101
4. If using advanced controller, use switch to toggle modes

Mode Selection (Dual ESP Setup)

• Default Mode (2-wheel): Switch LOW
  • Standard differential steering
  • Forward/reverse with turning
• Omni Mode (4-wheel): Switch HIGH
  • Full directional control
  • Rotation while moving

Architecture

Single-Board Version

┌─────────────┐     ┌──────────────┐     ┌───────────┐
│  Browser    │ WS  │   ESP32-C3   │ PWM │   Motors  │
│  Interface  │◄───►│  Web Server  │────►│   Driver  │
└─────────────┘     └──────────────┘     └───────────┘

Dual-Board Version

┌─────────────┐     ┌──────────────┐     ┌──────────────┐     ┌───────────┐
│  Browser    │ WS  │   Control    │     │    Drive     │ PWM │   Motors  │
│  Interface  │◄───►│    Board     │◄───►│    Board     │────►│   Driver  │
└─────────────┘     └──────────────┘     └──────────────┘     └───────────┘
                          WiFi              ESP-NOW

Component Overview

1. Web Interface (web_interface.cpp)

   • HTML/CSS layout
   • JavaScript joystick controls
   • WebSocket client
   • Real-time status display
   • UI event handling

2. Control Board (control.ino)

   • Web server hosting
   • User interface handling
   • ESP-NOW transmitter
   • OLED display updates
   • Connection management

3. Drive Board (drive.ino)

   • ESP-NOW receiver
   • Motor control logic
   • Failsafe handling
   • Automatic reconnection
   • Status monitoring

Communication Flow

Browser (Web Interface) → WebSocket → Control Board → ESP-NOW → Drive Board → Motors

Data Flow

User Input → JSON Command → ESP-NOW Packet → Motor Signal → Physical Movement

Master Controller

The file master_control.ino manages both Omni and Default modes through ESP-NOW communication. Default mode now also supports direct ESP-NOW control to the drive board.

Hardware Requirements

• ESP32-C3-Mini development board
• Dual H-Bridge motor driver
• 2x / 4x DC motors with wheels
• LiPo battery or AA batteries
• Chassis (3D printed, Laser Cut parts, etc)
• Basic electronic components
• Soldering is optional

Vehicle Builds

Omni-Drive Version *4-wheel omni-directional drive configuration*

Standard Version *2-wheel differential drive configuration*

Pin Configuration

Default Version (2-Wheel Drive)

Pin	Function
7	Left Motor PWM
0	Right Motor PWM
8	Left Motor Forward
9	Left Motor Reverse
4	Right Motor Forward
3	Right Motor Reverse

Omni Version (4-Wheel Drive)

Motor	Enable Pin (PWM)	Direction 1	Direction 2
Left Front	5	6	7
Right Front	20	21	3
Left Back	8	9	10
Right Back	2	1	0

Dual-Board Version

An alternative version using two ESP32 boards with ESP-NOW communication:

Features

• Long-range control (hundreds of meters)
• Direct peer-to-peer communication
• No WiFi network required
• Split control and drive functionality
• More reliable communication

Components

• Control Board: Handles web interface and user input
• Drive Board: Controls motors and receives commands
• ESP-NOW protocol for board-to-board communication

Benefits

• Separation of concerns
• Extended range capability
• Reduced latency
• More reliable motor control
• Independent WiFi and control systems

The code for this version is in:

• control.ino: Web interface and ESP-NOW transmitter
• drive.ino: Motor control and ESP-NOW receiver

Web Interface

The interface includes:

• Interactive joystick
• Real-time wheel speed indicators
• Quick control buttons
• Fine-tuning controls
• Status monitoring panel

Supporting Documentation

Design Files

*3D CAD model of chassis*

Control Display

*OLED status display on control board*

Wiring Diagrams

*Omni version wiring*

*Default version wiring*

Technical Details

Motor Control

• 10-bit PWM resolution (0-1023)
• 50Hz PWM frequency
• Minimum PWM threshold for reliable start
• Individual wheel speed tuning
• Proportional turn control

Network Configuration

• AP Mode: Web RC Car
• IP: 192.168.1.101
• No password required
• Optimized for low latency

Performance Tuning

1. Motor Dead Zone: Adjust MOTOR_MIN_PWM if motors don't start smoothly
2. Turn Sensitivity: Modify the turn rate mapping in the web interface
3. Wheel Balance: Use the tuning sliders to compensate for motor differences