How to Use ESP32 38-pin Expansion Board: Examples, Pinouts, and Specs

The ESP32 38-pin Expansion Board is a versatile development platform designed by Espressif to simplify prototyping and development with the ESP32 microcontroller. This board features 38 pins, providing easy access to the ESP32's GPIOs, power, and communication interfaces. It is ideal for Internet of Things (IoT) applications, smart devices, and embedded systems.

• IoT devices and smart home automation
• Wireless communication (Wi-Fi and Bluetooth)
• Sensor interfacing and data acquisition
• Robotics and motor control
• Prototyping and educational projects

The ESP32 38-pin Expansion Board is built around the ESP32 microcontroller, which integrates Wi-Fi and Bluetooth capabilities. Below are the key technical details:

The ESP32 38-pin Expansion Board provides access to the ESP32's GPIOs and other key interfaces. Below is the pinout description:

Note: Some GPIOs have specific functions or limitations (e.g., ADC, DAC, or touch sensing). Refer to the ESP32 datasheet for detailed pin capabilities.

1. Powering the Board:

   • Connect the board to a computer or USB power supply using a micro-USB cable.
   • Alternatively, supply 5V to the VIN pin and GND for external power.

2. Programming the ESP32:

   • Install the ESP32 board package in the Arduino IDE or use the Espressif IDF (IoT Development Framework).
   • Select the correct board type (e.g., "ESP32 Dev Module") and COM port in the IDE.
   • Write and upload your code to the ESP32 via USB.

3. Connecting Peripherals:

   • Use jumper wires to connect sensors, actuators, or other modules to the GPIO pins.
   • Ensure proper voltage levels (3.3V logic) to avoid damaging the board.

4. Using Wi-Fi and Bluetooth:

   • Configure Wi-Fi or Bluetooth settings in your code to enable wireless communication.
   • Use libraries like WiFi.h or BluetoothSerial.h for Arduino-based development.

• Voltage Levels: The ESP32 operates at 3.3V logic. Avoid connecting 5V signals directly to GPIO pins. Use level shifters if necessary.
• Pin Limitations: Some GPIOs (e.g., GPIO0, GPIO2) have specific boot mode functions. Avoid pulling these pins high or low during boot unless required.
• Power Supply: Ensure a stable power supply, especially when using Wi-Fi or Bluetooth, as these features can cause current spikes.

Below is an example of how to blink an LED connected to GPIO2:

// Define the GPIO pin for the LED
#define LED_PIN 2

void setup() {
  // Initialize the LED pin as an output
  pinMode(LED_PIN, OUTPUT);
}

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

  // Turn the LED off
  digitalWrite(LED_PIN, LOW);
  delay(1000); // Wait for 1 second
}

Tip: Use the onboard LED (usually connected to GPIO2) for quick testing.

1. Board Not Detected by Computer:

   • Ensure the USB cable is functional and supports data transfer.
   • Install the correct USB-to-serial driver (e.g., CP2102 or CH340).

2. Upload Fails with "Failed to Connect" Error:

   • Press and hold the "BOOT" button on the board while uploading the code.
   • Check the selected COM port and board type in the Arduino IDE.

3. Wi-Fi Connection Issues:

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

4. GPIO Pin Not Working:

   • Check if the pin is reserved for specific functions (e.g., boot mode).
   • Avoid using ADC2 pins when Wi-Fi is active, as they share resources.

Q: Can I power the ESP32 38-pin Expansion Board with a battery?
A: Yes, you can use a 3.7V LiPo battery with a suitable voltage regulator or connect a 5V source to the VIN pin.

Q: How do I reset the board?
A: Press the "EN" (Enable) button to reset the ESP32.

Q: Can I use the board with 5V logic sensors?
A: No, the ESP32 operates at 3.3V logic. Use level shifters to interface with 5V devices.

Q: What is the maximum current draw of the ESP32?
A: The ESP32 can draw up to 500mA during peak operation (e.g., Wi-Fi transmission). Ensure your power source can handle this.

By following this documentation, you can effectively use the ESP32 38-pin Expansion Board for your IoT and embedded projects.