How to Use ESP32 (30 pin): Examples, Pinouts, and Specs

The ESP32 (30 pin) is a powerful microcontroller designed for IoT and embedded system applications. It features built-in Wi-Fi and Bluetooth capabilities, making it an excellent choice for projects requiring wireless communication. With its 30 GPIO pins, the ESP32 offers a wide range of input/output functions, including ADC, DAC, PWM, I2C, SPI, and UART, making it versatile for various applications.

• IoT devices and smart home automation
• Wireless sensor networks
• Wearable technology
• Robotics and automation systems
• Data logging and remote monitoring
• Prototyping and educational projects

• Microcontroller: Tensilica Xtensa LX6 dual-core processor
• Clock Speed: Up to 240 MHz
• Flash Memory: 4 MB (varies by model)
• SRAM: 520 KB
• Wi-Fi: 802.11 b/g/n
• Bluetooth: v4.2 BR/EDR and BLE
• Operating Voltage: 3.3V
• Input Voltage Range: 5V (via USB) or 7-12V (via VIN pin)
• GPIO Pins: 30 (multipurpose, including ADC, DAC, PWM, I2C, SPI, UART)
• ADC Resolution: 12-bit
• DAC Resolution: 8-bit
• Power Consumption: Ultra-low power consumption in deep sleep mode (~10 µA)

The ESP32 (30 pin) has the following pinout:

1. Powering the ESP32:

   • Use the VIN pin to supply 7-12V, or connect a 5V USB power source.
   • Ensure the GND pin is connected to the common ground of your circuit.

2. Programming the ESP32:

   • Use a USB cable to connect the ESP32 to your computer.
   • Install the ESP32 board package in the Arduino IDE or use the ESP-IDF framework.
   • Select the correct board and port in the IDE before uploading code.

3. Connecting Peripherals:

   • Use GPIO pins for digital or analog input/output.
   • For communication protocols, connect devices to the appropriate pins (e.g., I2C, SPI, UART).

4. Wi-Fi and Bluetooth Setup:

   • Use the built-in libraries (e.g., WiFi.h or BluetoothSerial.h) to configure wireless communication.

• Voltage Levels: The ESP32 operates at 3.3V logic levels. Avoid connecting 5V signals directly to GPIO pins.
• Boot Mode: Ensure GPIO0 is pulled low during programming to enter boot mode.
• Power Supply: Use a stable power source to avoid unexpected resets or instability.
• Deep Sleep: Utilize deep sleep mode for low-power applications to extend battery life.

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

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

const char* ssid = "Your_SSID";       // Replace with your Wi-Fi network name
const char* password = "Your_Password"; // Replace with your Wi-Fi password
const int ledPin = 2;                 // GPIO2 is typically connected to the onboard LED

void setup() {
  pinMode(ledPin, OUTPUT);            // Set the LED pin as an output
  Serial.begin(115200);               // Start the serial communication
  WiFi.begin(ssid, password);         // Connect to the Wi-Fi network

  Serial.print("Connecting to Wi-Fi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nConnected to Wi-Fi!");
}

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. ESP32 Not Connecting to Wi-Fi:

   • Double-check the SSID and password in your code.
   • Ensure the Wi-Fi network is active and within range.
   • Restart the ESP32 and router if necessary.

2. Upload Fails or Timeout Errors:

   • Ensure the correct board and port are selected in the Arduino IDE.
   • Hold the BOOT button while uploading to force boot mode.
   • Check the USB cable and connection.

3. ESP32 Keeps Resetting:

   • Verify the power supply is stable and sufficient.
   • Avoid excessive current draw from GPIO pins.

4. GPIO Pin Not Working:

   • Confirm the pin is not reserved for internal functions (e.g., GPIO0, GPIO2 during boot).
   • Check for short circuits or incorrect wiring.

• Can the ESP32 handle 5V logic?
  No, the ESP32 operates at 3.3V logic levels. Use a level shifter for 5V signals.

• How do I use the ESP32's Bluetooth?
  Use the BluetoothSerial library in the Arduino IDE to configure and communicate via Bluetooth.

• What is the maximum number of devices the ESP32 can connect to via Wi-Fi?
  The ESP32 can act as a Wi-Fi access point and support up to 10 devices by default, but this can be increased with custom configurations.

• How do I reduce power consumption?
  Use deep sleep mode and disable unused peripherals to minimize power usage.