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

The ESP32 - Expansion Board is a versatile add-on module designed to augment the capabilities of the ESP32 microcontroller. It provides additional hardware interfaces and power management features, enabling users to connect a wide range of peripherals and sensors. Common applications include IoT devices, home automation systems, and prototyping for embedded systems.

• Operating Voltage: 3.3V
• Input Voltage (recommended): 5V to 12V
• Input Voltage (limit): 6V to 20V
• Digital I/O Pins: 22
• Analog Input Pins: 6 (ADC channels)
• Analog Output Pins: 2 (DAC channels)
• Flash Memory: 4MB
• SRAM: 520 KB
• Clock Speed: 240 MHz
• Wi-Fi: 802.11 b/g/n
• Bluetooth: v4.2 BR/EDR and BLE

1. Powering the Board:

   • Connect a 5V to 12V power supply to the VIN pin and GND.
   • Alternatively, power the board via the micro-USB port.

2. Interfacing with Peripherals:

   • Use the GPIO pins to connect sensors, actuators, or other modules.
   • Analog sensors can be connected to ADC pins for reading analog values.
   • Use DAC pins for analog output to devices like audio jacks or LED drivers.

3. Programming the ESP32:

   • Connect the board to a computer using a micro-USB cable.
   • Use the Arduino IDE or other compatible software to upload your code.

• Ensure that the input voltage does not exceed the recommended limit to prevent damage.
• When using Wi-Fi or Bluetooth, place the board in a location with minimal interference.
• Use proper decoupling capacitors close to the power pins to reduce noise.
• Avoid drawing more current than the GPIO pins can handle (typically 12 mA per pin).

• Board not powering up: Check the power supply and connections to VIN and GND.
• Cannot upload code: Ensure the correct drivers are installed and the board is selected in the IDE.
• Wi-Fi/Bluetooth not functioning: Verify antenna connections and check for signal interference.

• If the board does not power up, try using a different power supply or USB cable.
• For code upload issues, double-check the USB port and board settings in the IDE.
• For wireless connectivity problems, ensure that the board's firmware is up to date.

Q: Can I power the board using the 3V3 pin? A: It is not recommended to power the board through the 3V3 pin as it bypasses the onboard voltage regulator.

Q: How many GPIO pins can be used simultaneously? A: All 22 GPIO pins can be used, but be mindful of the total current draw.

Q: What is the maximum analog input voltage for the ADC pins? A: The maximum voltage for the ADC pins is 3.3V.

Below is an example code snippet for blinking an LED connected to a GPIO pin on the ESP32 - Expansion Board using the Arduino IDE.

// Define the LED pin
const int ledPin = 2; // Use GPIO 2 for the LED

// Setup function runs once when you press reset or power the board
void setup() {
  // Initialize the LED pin as an output
  pinMode(ledPin, OUTPUT);
}

// Loop function runs over and over again forever
void loop() {
  digitalWrite(ledPin, HIGH);   // Turn the LED on
  delay(1000);                  // Wait for a second
  digitalWrite(ledPin, LOW);    // Turn the LED off
  delay(1000);                  // Wait for a second
}

Remember to adjust the ledPin variable to match the GPIO pin you have connected your LED to. This code will blink the LED on and off every second.