maker-esp32-mini

A quadruple DC/stepper motor driver development board based on Espressif ESP32-DOWD-V3, designed for maker education.

📖 Table of Contents

Introduction
Features
Specifications
Pinout
Hardware Connection
Getting Started
Example Programs
Library Installation
Antenna Switching
Mechanical Dimensions
FAQ
References
License

🔍 Introduction

Maker-ESP32-Mini is a maker education development board based on the Espressif ESP32-DOWD-V3 chip. It features 4MB onboard Flash and integrates 2.4 GHz Wi-Fi and Bluetooth dual-mode connectivity. The board includes a quad DC motor driver chip with both PH2.0 horizontal SMD connectors and 2.54mm standard pin headers for motor outputs, capable of directly driving TT DC motors, LEGO motors, and other general-purpose motors. It also provides 4 independent servo ports with a peak current of up to 1A per channel.

Compared to the previous Maker-ESP32, this product has been comprehensively upgraded:

IO0 (BOOT) pin is routed to a dedicated tactile switch
Board dimensions with enclosure reduced to 56 × 72mm, perfectly matching 7 × 9 LEGO grid spacing for direct mounting
New PH2.0 power input connector with dedicated buck-boost power management IC
Under light-load conditions, a single 3.7V lithium battery or standard battery pack can provide stable power

✨ Features

✅ Original Espressif ESP32-DOWD-V3 chip
✅ Onboard PCB antenna and IPEX antenna connector (switchable)
✅ 4 DC motor ports, max continuous current 3A
✅ 2 stepper motor ports (shared IO with DC motors)
✅ 4 servo ports, peak current 1A per channel
✅ 5 I2C pin headers, 1 SPI pin header
✅ 3 VIN pin headers and 3 5V pin headers
✅ 12 IO pins broken out
✅ Supports Mixly, Arduino IDE, MicroPython, Mind+
✅ LEGO grid compatible for direct mounting

📊 Specifications

Parameter	Specification
MCU	ESP32-DOWD-V3
Flash	4MB
ROM	448 KB
SRAM	520 KB
RTC SRAM	16 KB
Wireless	Wi-Fi 2.4 GHz / Bluetooth dual-mode
DC Motor Ports	M0: 27, 13; M1: 4, 2; M2: 17, 12; M3: 15, 14
Stepper Motor Ports	Stepper1: 27, 13, 4, 2; Stepper2: 17, 12, 15, 14
Motor Max Continuous Current	3A
Servo Ports	25, 26, 32, 33
DC Input Voltage	3.7–12V (5.5-2.1mm)
5V Max Output Current	3A
Motor Port Max Output Current	4A
Dimensions	70mm × 54mm
PCB Thickness	1.6mm
Net Weight	26g

⚠️ Important: For full-load operation, ensure the power supply current is ≥ 4A and the input voltage is ≥ 7.4V. Otherwise, the MCU may reset unexpectedly.

📌 Pinout

Interface Overview

Interface	Description
Type-C	Programming and power
Power Switch	Main power on/off
6-12V PH2.0 Input	Lithium battery input
6-12V DC Input	DC power input (5.5-2.1mm)
VIN/5V Headers	Power output/input pins
SPI Header	SPI communication
I2C Header	I2C communication
Analog/Digital Header	Digital/Analog IO breakout
Servo Ports	4-channel servo output
OLED Header	OLED display interface
Motor Ports M0-M3	DC motor outputs
Stepper Ports	Stepper1 / Stepper2
Motor/IO Switch	Motor/IO mode selection

Important Notes

Motor and IO Switch: When the DIP switch is set to the IO side, M2 and M3 motor ports are disabled and function as regular GPIOs. When set to M3A/M3B/M4A/M4B, M2 and M3 function as motor ports.
ESP32 Chip Characteristics: Under the Arduino framework, pins 34, 35, 36, 39 cannot be used as outputs. When used as inputs, internal pull-up/pull-down resistors cannot be enabled.
Wi-Fi Usage: Use 2.4GHz networks only; 5GHz networks are not supported.

🔌 Hardware Connection

DC Motor Ports

Motor Port	Pins
M0	27, 13
M1	4, 2
M2	17, 12
M3	15, 14

Compatible with TT DC motors, LEGO motors, and other general-purpose motors.

Stepper Motor Ports

Stepper Port	Pins
Stepper1	27, 13, 4, 2
Stepper2	17, 12, 15, 14

28BYJ-48 Stepper Motor Wiring (Stepper1 example):

Wire Color	Pin
Orange	A01 (27)
Pink	A02 (13)
Blue	A03 (4)
Yellow	A04 (2)
Red	5V

42 Stepper Motor (Bipolar, 4-wire) Wiring:

Motor Wire	Stepper1 Pin	Stepper2 Pin
A+	A01 (27)	B01 (17)
A-	A02 (13)	B02 (12)
B+	A03 (4)	B03 (15)
B-	A04 (2)	B04 (14)

Servo Ports

Servo Channel	Pin
Servo1	25
Servo2	26
Servo3	32
Servo4	33

Power Inputs

PH2.0 Connector: 6–12V input
DC Jack: 5.5-2.1mm, 6–12V input
VIN Headers: 3 pins
5V Headers: 3 pins

🚀 Getting Started

1. Driver Installation

Please refer to the CH340G Driver Installation Guide.

2. Arduino IDE Setup

Download and install Arduino IDE
Install ESP32 board support:
- Open File → Preferences
- Add the following URL to Additional Boards Manager URLs:
```
https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json
```
- Open Tools → Board → Boards Manager
- Search for esp32 and install
Select board: Tools → Board → ESP32 Arduino → ESP32 Dev Module

📌 Note: When using Arduino IDE, please update esp32 to the latest version.

3. Uploading Programs

For program upload instructions, please refer to the ESP32 Upload Guide.

💡 Example Programs

DC Motor Control

// DC Motor Control Example
// M0: 27, 13; M1: 4, 2; M2: 17, 12; M3: 15, 14

#define MOTOR_M0_A 27
#define MOTOR_M0_B 13

void setup() {
  pinMode(MOTOR_M0_A, OUTPUT);
  pinMode(MOTOR_M0_B, OUTPUT);
}

void loop() {
  // Forward
  digitalWrite(MOTOR_M0_A, HIGH);
  digitalWrite(MOTOR_M0_B, LOW);
  delay(2000);

  // Reverse
  digitalWrite(MOTOR_M0_A, LOW);
  digitalWrite(MOTOR_M0_B, HIGH);
  delay(2000);

  // Stop
  digitalWrite(MOTOR_M0_A, LOW);
  digitalWrite(MOTOR_M0_B, LOW);
  delay(1000);
}

Stepper Motor Control (28BYJ-48)

Required Library: Bonezeqi_ULN2003_Stepper v1.0.1

#include <Bonezeqi_ULN2003_Stepper.h>

// Define stepper motor pins (Stepper1)
#define IN1 27
#define IN2 13
#define IN3 4
#define IN4 2

// Initialize stepper motor
Bonezeqi_ULN2003_Stepper stepper(IN1, IN2, IN3, IN4);

void setup() {
  stepper.begin();
  stepper.setSpeed(5); // Set speed
}

void loop() {
  stepper.step(100);  // Forward 100 steps
  delay(1000);
  stepper.step(-100); // Reverse 100 steps
  delay(1000);
}

Stepper Motor Control (42 Stepper)

Required Library: AccelStepper v1.64

#include <AccelStepper.h>

// Define stepper motor pins (Stepper1)
#define MOTOR_A_PLUS  27
#define MOTOR_A_MINUS 13
#define MOTOR_B_PLUS  4
#define MOTOR_B_MINUS 2

// Initialize AccelStepper (Full-step mode)
AccelStepper stepper(AccelStepper::FULL4WIRE, MOTOR_A_PLUS, MOTOR_A_MINUS, MOTOR_B_PLUS, MOTOR_B_MINUS);

void setup() {
  stepper.setMaxSpeed(1000);    // Max speed
  stepper.setAcceleration(500); // Acceleration
}

void loop() {
  stepper.moveTo(200);   // Move to position 200
  stepper.runToPosition();
  delay(1000);

  stepper.moveTo(0);     // Return to position 0
  stepper.runToPosition();
  delay(1000);
}

Servo Control

#include <ESP32Servo.h>

Servo servo1;
Servo servo2;

void setup() {
  servo1.attach(25); // Servo 1 on pin 25
  servo2.attach(26); // Servo 2 on pin 26
}

void loop() {
  // Servo 1: 0° to 180°
  for (int angle = 0; angle <= 180; angle++) {
    servo1.write(angle);
    delay(15);
  }
  // Servo 1: 180° to 0°
  for (int angle = 180; angle >= 0; angle--) {
    servo1.write(angle);
    delay(15);
  }
}

OLED Display

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET    -1

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

void setup() {
  Wire.begin(21, 22); // SDA, SCL
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;);
  }
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.println("Maker-ESP32-Mini");
  display.display();
}

void loop() {
  // Update display content
}

📦 Library Installation

Installing the ULN2003 Library

Open Arduino IDE Library Manager:
- Menu: Tools → Manage Libraries...
- Shortcut: Ctrl+Shift+I (Windows/Linux) or Cmd+Shift+I (Mac)
Search for: ULN2003
Find the Bonezeqi_ULN2003_Stepper library
Select version 1.0.1
Click Install

Installing the AccelStepper Library

Open Arduino IDE Library Manager
Search for AccelStepper
Select version 1.64
Click Install

Installing the ESP32Servo Library

Open Arduino IDE Library Manager
Search for ESP32Servo
Click Install

📡 Antenna Switching

As shown in the figure, when the inductor is placed toward direction 1, the onboard PCB antenna is active. When placed toward direction 2, the IPEX antenna connector is active.

📐 Mechanical Dimensions

3D

Overall dimensions: 70.000 mm × 54.000 mm
Mounting hole spacing: 48.000 mm × 4.200 mm
PCB thickness: 1.6 mm

❓ FAQ

Q: Mixly program upload fails?

A:

Ensure the Mixly installation path does not contain Chinese characters, spaces, or special characters. Place it in the root directory with a shallow folder hierarchy, e.g., D:\mixly2.0-win32-x64.
Check that the correct serial port is selected. If no port appears, install the CH340G driver first. Make sure the port is not occupied by another application.
Check the program for errors.

Q: The motor program uploaded successfully but the motor does not rotate?

A:

The motor requires DC power (3.7–12V). We recommend using two 3.7V lithium batteries. Make sure the power switch is turned ON.
If step 1 is complete and the issue persists, check that the Motor and IO Switch is set to the motor side (marked ON).
Verify that the motor pins defined in the program match the actual motor pins.

Q: Wi-Fi cannot connect?

A: Use a 2.4GHz network only. ESP32 does not support 5GHz networks.

Q: The MCU resets unexpectedly?

A: For full-load operation, ensure the power supply current is ≥ 4A and the input voltage is ≥ 7.4V.

🔗 References

📄 License

This project is licensed under the MIT License. See the LICENSE file for details.

🤝 Contributing

Issues and Pull Requests are welcome!

Fork this repository
Create your feature branch (git checkout -b feature/AmazingFeature)
Commit your changes (git commit -m 'Add some AmazingFeature')
Push to the branch (git push origin feature/AmazingFeature)
Open a Pull Request

📞 Contact

Technical Support: support@null-lab.com.
Whatsapp: +86 188 9844 2841

Maker-ESP32-Mini — Making Maker Education Simpler! 🚀

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