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

The ESP32 is a powerful microcontroller with built-in Wi-Fi and Bluetooth capabilities, making it an excellent choice for Internet of Things (IoT) applications and embedded systems. With its 30-pin configuration, the ESP32 offers a wide range of input/output (I/O) options, enabling developers to connect sensors, actuators, and other peripherals with ease. Its dual-core processor and low-power consumption make it suitable for both high-performance and energy-efficient designs.

• IoT devices (e.g., smart home systems, wearables)
• Wireless communication (Wi-Fi and Bluetooth)
• Data logging and remote monitoring
• Robotics and automation
• Prototyping and development of embedded systems

The ESP32 (30 pin) microcontroller is packed with features that make it versatile and powerful. Below are its key technical details:

• Processor: Dual-core Xtensa® 32-bit LX6 CPU
• 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 pins (multipurpose)
• ADC Channels: 18 (12-bit resolution)
• DAC Channels: 2 (8-bit resolution)
• PWM Outputs: Up to 16 channels
• I2C, SPI, UART: Multiple communication interfaces
• Power Consumption: Ultra-low power modes available

The ESP32 (30 pin) has a standard pinout. Below is a table describing the key pins and their functions:

1. Powering the ESP32:

   • Use the VIN pin to supply 7-12V, or connect a 5V USB cable to the micro-USB port.
   • Ensure the 3.3V pin is used only for low-power external components.

2. Connecting Peripherals:

   • Use GPIO pins for digital I/O, ADC, PWM, or communication protocols (I2C, SPI, UART).
   • Connect sensors, actuators, or other devices to the appropriate pins based on their requirements.

3. Programming the ESP32:

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

4. Boot Mode:

   • To enter bootloader mode, hold the BOOT button while pressing the EN (reset) button.

• Always use a level shifter when interfacing 5V logic devices with the ESP32's 3.3V GPIO pins.
• Avoid drawing more than 500mA from the 3.3V pin to prevent damage.
• Use decoupling capacitors near the power pins to stabilize the power supply.
• Ensure proper grounding to avoid noise and interference in high-frequency applications.

Below is an example of how to use the ESP32 to read a sensor value and send it over Wi-Fi:

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

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

void setup() {
  Serial.begin(115200); // Initialize serial communication at 115200 baud
  WiFi.begin(ssid, password); // Connect to Wi-Fi network

  // Wait for connection
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to Wi-Fi...");
  }
  Serial.println("Connected to Wi-Fi!");
}

void loop() {
  // Example: Read an analog value from GPIO34
  int sensorValue = analogRead(34); // Read from ADC pin GPIO34
  Serial.print("Sensor Value: ");
  Serial.println(sensorValue); // Print the sensor value to the Serial Monitor

  delay(1000); // Wait for 1 second before reading again
}

1. ESP32 Not Connecting to Wi-Fi:

   • Ensure the SSID and password are correct.
   • Check if the router is within range and supports 2.4 GHz (ESP32 does not support 5 GHz).

2. Upload Fails in Arduino IDE:

   • Verify the correct COM port and board are selected in the IDE.
   • Hold the BOOT button while uploading the code to enter bootloader mode.

3. GPIO Pins Not Working:

   • Check if the pin is configured correctly in the code (e.g., pinMode()).
   • Ensure the pin is not being used for another function (e.g., UART, SPI).

4. Power Issues:

   • Use a stable power supply to avoid brownouts.
   • Check if the current draw of connected peripherals exceeds the ESP32's limits.

Q: Can the ESP32 operate on battery power?
A: Yes, the ESP32 can be powered by a LiPo battery connected to the VIN pin. Use a voltage regulator if needed.

Q: How do I reset the ESP32?
A: Press the EN (reset) button to restart the microcontroller.

Q: Can I use the ESP32 with 5V sensors?
A: Yes, but you must use a level shifter to convert 5V signals to 3.3V to avoid damaging the GPIO pins.