How to Use ESP32 Dev board (20 pins): Examples, Pinouts, and Specs

The ESP32 Dev Board (20 pins) is a versatile microcontroller development board powered by the ESP32 chip. It features built-in Wi-Fi and Bluetooth capabilities, making it an excellent choice for Internet of Things (IoT) projects, wireless communication, and rapid prototyping. The board is compact, energy-efficient, and supports a wide range of peripherals, making it suitable for both hobbyists and professionals.

• IoT devices and smart home automation
• Wireless sensor networks
• Wearable technology
• Robotics and automation
• Data logging and remote monitoring
• Prototyping for Wi-Fi and Bluetooth-enabled devices

• Microcontroller: ESP32 dual-core processor
• Clock Speed: Up to 240 MHz
• Flash Memory: 4 MB (varies by model)
• SRAM: 520 KB
• Connectivity: Wi-Fi (802.11 b/g/n), Bluetooth 4.2 (Classic and BLE)
• Operating Voltage: 3.3V
• Input Voltage (via VIN pin): 5V
• GPIO Pins: 20 (multipurpose, including ADC, DAC, PWM, I2C, SPI, UART)
• Analog Input Pins: 16 (12-bit ADC resolution)
• Digital Output Pins: 20
• PWM Channels: 16
• DAC Channels: 2 (8-bit resolution)
• Power Consumption: Ultra-low power consumption in deep sleep mode (~10 µA)
• Operating Temperature: -40°C to 85°C

The ESP32 Dev Board (20 pins) has the following pinout:

1. Powering the Board:

   • Use the VIN pin (5V) or connect via the micro-USB port to power the board.
   • Ensure the power supply provides sufficient current (at least 500 mA).

2. Programming the Board:

   • Install the ESP32 board package in the Arduino IDE or use the ESP-IDF framework.
   • Connect the board to your computer via a USB cable.
   • Select the correct board and port in the Arduino IDE.
   • Write your code and upload it to the board.

3. Connecting Peripherals:

   • Use GPIO pins for digital input/output.
   • Use ADC pins for analog input (e.g., sensors).
   • Use I2C or SPI pins for communication with external devices like displays or sensors.

• Voltage Levels: The ESP32 operates at 3.3V. Avoid applying 5V directly to GPIO pins to prevent damage.
• Boot Mode: Ensure IO0 is pulled low during programming to enter boot mode.
• Deep Sleep Mode: Use deep sleep mode to conserve power in battery-powered applications.
• Pull-up/Pull-down Resistors: Some GPIO pins require external pull-up or pull-down resistors for proper operation.

The following example demonstrates how to connect the ESP32 to a Wi-Fi network and blink an LED connected to GPIO2:

#include <WiFi.h> // Include the Wi-Fi library

// Replace with your network credentials
const char* ssid = "Your_SSID";
const char* password = "Your_PASSWORD";

const int ledPin = 2; // GPIO2 is connected to the onboard LED

void setup() {
  pinMode(ledPin, OUTPUT); // Set GPIO2 as an output pin
  Serial.begin(115200);    // Start serial communication at 115200 baud

  // Connect to Wi-Fi
  Serial.print("Connecting to Wi-Fi");
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWi-Fi connected!");
  Serial.print("IP Address: ");
  Serial.println(WiFi.localIP());
}

void loop() {
  digitalWrite(ledPin, HIGH); // Turn the LED on
  delay(1000);                // Wait for 1 second
  digitalWrite(ledPin, LOW);  // Turn the LED off
  delay(1000);                // Wait for 1 second
}

1. The board is not detected by the computer:

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

2. Upload fails with a timeout error:

   • Check that the correct board and port are selected in the Arduino IDE.
   • Hold the BOOT button while uploading to force the board into programming mode.

3. Wi-Fi connection issues:

   • Verify the SSID and password are correct.
   • Ensure the Wi-Fi network is within range and not overloaded.

4. GPIO pins not working as expected:

   • Check if the pin is being used for another function (e.g., ADC, UART).
   • Avoid using pins reserved for internal functions (e.g., IO6-IO11 for flash memory).

• Can I power the ESP32 with a battery?
  Yes, you can use a 3.7V LiPo battery connected to the 3V3 pin or a 5V source connected to the VIN pin.

• What is the maximum current output of the 3V3 pin?
  The 3V3 pin can supply up to 500 mA, depending on the input power source.

• Can I use the ESP32 with other IDEs?
  Yes, the ESP32 is compatible with the Arduino IDE, PlatformIO, and the ESP-IDF framework.

• How do I reset the board?
  Press the RST button or toggle the EN pin to reset the board.