How to Use ESP32-DevKitM-1: Examples, Pinouts, and Specs

The ESP32-DevKitM-1 is a compact development board based on the ESP32-MINI-1 module, which integrates the powerful ESP32 chip. This board is equipped with dual-mode Wi-Fi and Bluetooth capabilities, making it an excellent choice for Internet of Things (IoT) applications. Its small form factor and versatile GPIO pins allow developers to interface with a wide range of sensors, actuators, and other peripherals.

• Smart home devices (e.g., connected lights, thermostats)
• Wearable electronics
• Industrial IoT systems
• Wireless data logging and monitoring
• Prototyping Bluetooth Low Energy (BLE) and Wi-Fi-enabled devices

The ESP32-DevKitM-1 is designed to provide robust performance in a compact package. Below are its key technical details:

• Microcontroller: ESP32-MINI-1 module (based on ESP32 chip)
• Wireless Connectivity: Wi-Fi (802.11 b/g/n) and Bluetooth (v4.2 BR/EDR and BLE)
• Operating Voltage: 3.3V
• Input Voltage Range: 5V (via USB) or 3.3V (via external power supply)
• GPIO Pins: 15 (configurable for digital I/O, PWM, ADC, etc.)
• Flash Memory: 4 MB
• Operating Temperature: -40°C to 85°C
• Dimensions: 48.0 mm x 25.5 mm

The ESP32-DevKitM-1 features a 16-pin layout. Below is the pinout and description:

The ESP32-DevKitM-1 is versatile and easy to use in a variety of projects. Below are the steps and best practices for using this development board.

1. Powering the Board:

   • Connect the board to a computer or USB power source using a micro-USB cable.
   • Alternatively, supply 3.3V directly to the 3V3 pin or 5V to the 5V pin.

2. Programming the Board:

   • Install the Arduino IDE or ESP-IDF for development.
   • Add the ESP32 board support package to the Arduino IDE via the Boards Manager.
   • Select "ESP32 Dev Module" as the board type in the IDE.

3. Connecting Peripherals:

   • Use the GPIO pins to connect sensors, actuators, or other devices.
   • Ensure that the voltage levels of connected peripherals are compatible with the 3.3V logic of the ESP32.

4. Uploading Code:

   • Write your code in the Arduino IDE or ESP-IDF.
   • Connect the board to your computer via USB and select the correct COM port.
   • Click the upload button to flash the code onto the ESP32.

• Voltage Levels: Ensure that all connected peripherals operate at 3.3V logic levels to avoid damaging the board.
• Boot Mode: To enter bootloader mode, hold down the IO0 button while pressing the EN button.
• Power Supply: Use a stable power source to avoid unexpected resets or instability.
• Wi-Fi and Bluetooth: Avoid placing the board in metal enclosures, as this can interfere with wireless signals.

Below is an example of how to use the ESP32-DevKitM-1 to read data from a DHT11 temperature and humidity sensor and send it to a serial monitor:

#include <WiFi.h>
#include <DHT.h>

// Define the DHT sensor type and pin
#define DHTPIN 4       // GPIO4 is connected to the DHT sensor
#define DHTTYPE DHT11  // DHT11 sensor type

DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(115200);  // Initialize serial communication
  dht.begin();           // Initialize the DHT sensor
  Serial.println("ESP32 DHT11 Example");
}

void loop() {
  delay(2000);  // Wait 2 seconds between readings

  // Read temperature and humidity values
  float humidity = dht.readHumidity();
  float temperature = dht.readTemperature();

  // Check if the readings are valid
  if (isnan(humidity) || isnan(temperature)) {
    Serial.println("Failed to read from DHT sensor!");
    return;
  }

  // Print the readings to the serial monitor
  Serial.print("Humidity: ");
  Serial.print(humidity);
  Serial.print("%  Temperature: ");
  Serial.print(temperature);
  Serial.println("°C");
}

1. Board Not Detected by Computer:

   • Ensure the USB cable is functional and supports data transfer.
   • Install the correct USB-to-serial driver for the ESP32.

2. Code Upload Fails:

   • Check that the correct COM port and board type are selected in the IDE.
   • Hold down the IO0 button while pressing the EN button to enter bootloader mode.

3. Wi-Fi Connection Issues:

   • Verify the SSID and password in your code.
   • Ensure the router is within range and supports 2.4 GHz Wi-Fi.

4. Unstable Operation:

   • Use a stable power source with sufficient current (at least 500 mA).
   • Avoid connecting peripherals that draw excessive current.

• Debugging: Use the Serial Monitor in the Arduino IDE to print debug messages.
• Resetting the Board: Press the EN button to reset the ESP32 if it becomes unresponsive.
• Firmware Updates: Update the ESP32 firmware using the ESP-IDF tools for improved stability and features.

By following this documentation, you can effectively use the ESP32-DevKitM-1 in your IoT and embedded systems projects.