ESP32 Motor Controller

A collection of motor control implementations for the ESP32-S2 Mini with DRV8833 motor driver.

Version Overview

v1: Basic Test

• Simple motor test sequence
• Basic forward/backward/turn movements
• No fault detection

v2: Mode System

• Multiple movement modes (wander, rotate, test)
• Mode switching logic
• Basic error handling

v3: Power Management

• Improved power handling
• Speed ramping
• Basic fault detection
• Reduced motor speeds

v4: Organic Movement

• Slow, rock-like movement patterns
• Advanced fault detection
• PWM-based motor control
• Random movement generation
• Detailed debugging

v5: Simple Forward Test

• Continuous forward movement
• Basic PWM control
• Minimal code for testing
• No mode switching or complex logic

v6: All Directions Test

• Tests all motor directions sequentially
• Basic PWM control
• Auxiliary pin control (GPIO39)
• Cycle between directions automatically

Hardware

• ESP32-S2 Mini (Lolin)
• DRV8833 Motor Driver
• 2 DC Motors
• Power Supply (5V recommended)

Pin Configuration

• Motor A: GPIO11 (IN1), GPIO9 (IN2)
• Motor B: GPIO7 (IN1), GPIO5 (IN2)
• Fault Pin: GPIO12
• LED: GPIO15

Project Structure

This project is organized into two versions:

• v1: Uses the ESP32-CAM and L298N motor driver (older, traditional driver)
• v2: Uses the ESP32-S2 Mini and DRV8833 motor driver (more efficient, modern setup)

Each version contains its own complete implementation for its respective hardware. For detailed wiring and implementation specifics, see the WIRING.md file in each subproject folder.

Hardware Requirements

Common Components for Both Versions

• 2-wheel drive robot car chassis with DC motors
• Jumper wires
• Small breadboard (optional, for cleaner wiring)

Version Specific Components

• v1:

  • ESP32-CAM development board
  • L298N dual H-bridge motor driver (detailed documentation)
  • MP1584EN buck converter module (for power regulation)
  • Power supply for motors (battery pack/power bank)

• v2:

  • Wemos ESP32-S2 Mini development board
  • DRV8833 dual H-bridge motor driver (detailed documentation)
  • 5V powerbank with USB output
  • USB splitter/hub or adapter
  • USB in-line power switch (for global power control)
  • Step-up converter (boosts 5V from powerbank to 6V for motors)

Power Supply Architecture Differences

The v1 and v2 versions use different power supply approaches:

v1 Power Supply:

• Battery/power source → MP1584EN buck converter → ESP32-CAM (5V)
• Battery/power source → L298N motor driver (higher voltage)

v2 Power Supply:

• Powerbank USB output → Global power switch → USB splitter/hub
  • First output: USB-C connection to ESP32-S2 Mini (direct connection)
  • Second output: 5V to Step-up converter → DRV8833 motor driver (6V)

The v2 setup uses a true global power switch that controls the entire system with a single switch, turning both the microcontroller and motors on/off together.

Hardware Comparison

Microcontroller Comparison

Feature	v1: ESP32-CAM	v2: ESP32-S2 Mini
USB Connection	External programmer required	Built-in USB-C port
Size	Larger	Compact
Power Input	5V via pins	Direct USB-C
Programming	Via serial adapter	Native USB
Unnecessary Features	Camera module	None
Form Factor	Less robot-friendly	Ideal for robotics

Motor Driver Comparison

Feature	v1: L298N	v2: DRV8833
Efficiency	~70%	>90%
Control Pins	6 total	4 total
Heat Generation	High	Low
Size	Large	Compact
Control Method	Enable + Direction pins	PWM on all pins

Power Control Comparison

Feature	v1 Approach	v2 Approach
Power Switch	Controls motors only	True global control (entire system)
Power Source	Separate paths	Single source with distribution
Wiring Complexity	More complex	Simplified with USB connectivity
Development Mode	ESP32 always on	System fully controlled by one switch

For detailed pin connections, wiring diagrams, and implementation specifics, see:

• L298N Wiring & Implementation Guide
• DRV8833 Wiring & Implementation Guide

Software Setup

This project uses PlatformIO for development and deployment:

1. Install Visual Studio Code
2. Install the PlatformIO extension
3. Clone or download this repository
4. Open either the v1 or v2 project folder in VS Code
5. Build and upload the project using PlatformIO

V2 Programming Advantage

The v2 version with ESP32-S2 Mini can be programmed directly via USB-C connection without additional hardware, making development and testing significantly easier. During development, you can disconnect the powerbank and connect the ESP32-S2 Mini directly to your computer.

Features

Movement Modes

The robot car supports three different movement modes:

1. Test Mode: Demonstrates basic movements in a sequence
2. Wander Mode: Robot randomly wanders with organic movements
3. Rotate Mode: Robot slowly rotates around its axis

By default, the robot switches between Wander Mode and Rotate Mode every 30 seconds.

Basic Movement Functions

The code includes the following standard movement functions:

• moveForward(speed): Moves the robot forward
• moveBackward(speed): Moves the robot backward
• turnLeft(speed): Turns the robot left
• turnRight(speed): Turns the robot right
• stopMotors(): Stops all motor movement

Differential Steering

Advanced movement control is achieved through differential steering:

• moveDifferential(leftSpeed, rightSpeed): Allows independent control of each wheel
• curveLeft(leftSpeed, rightSpeed): Creates curved left movement
• curveRight(leftSpeed, rightSpeed): Creates curved right movement

Speed Control

All movement functions support variable speed control through PWM, with speed values ranging from 0 (stop) to 255 (full speed).

Movement Modes in Detail

Test Mode

Cycles through a series of basic movements to test motor functionality:

1. Forward → Stop → Backward → Stop → Left turn → Stop → Right turn → Stop

Wander Mode

Implements organic, randomized movement with varying speeds and paths:

• Straight forward movement
• Gentle left and right curves
• Sharp left and right curves
• 180° spin turns
• Backward movement
• Random stops

Rotate Mode

Performs a slow, controlled rotation around the robot's center:

• Rotates in a random direction (left or right)
• Changes direction every 10 seconds
• Uses reduced speed for careful rotation

Customization

You can customize the pin assignments at the beginning of the motor_control.cpp file if you need to use different GPIO pins on your microcontroller.

To implement additional movement modes or alter the existing ones, refer to the corresponding mode files in the src directory.

Troubleshooting

Basic troubleshooting tips are included in the WIRING.md file for each version:

• L298N Troubleshooting
• DRV8833 Troubleshooting

Project Structure

For each version (v1 and v2):

• platformio.ini: PlatformIO configuration
• WIRING.md: Detailed wiring and implementation documentation
• include/motor_control.h: Header file for motor control functions
• include/movement_modes.h: Defines the movement modes enum
• include/test_mode.h: Header for test mode
• include/wander_mode.h: Header for wander mode
• include/rotate_mode.h: Header for rotate mode
• src/motor_control.cpp: Motor control functions implementation
• src/main.cpp: Main program with setup, loop, and mode switching logic
• src/test_mode.cpp: Test mode implementation
• src/wander_mode.cpp: Wander mode implementation with organic movement
• src/rotate_mode.cpp: Rotate mode implementation

License

This project is open source and available under the MIT License.