How to Use ESP32: Examples, Pinouts, and Specs

The ESP32, manufactured by Espressif, is a low-cost, low-power system on a chip (SoC) with integrated Wi-Fi and Bluetooth capabilities. It is designed for a wide range of applications, including Internet of Things (IoT) devices, smart home systems, wearable electronics, and industrial automation. The ESP32 CH340 variant includes a CH340 USB-to-serial converter, making it easier to program and debug the module via a USB connection.

With its dual-core processor, extensive GPIO options, and support for multiple communication protocols, the ESP32 is a versatile and powerful choice for embedded systems development.

• IoT devices and smart home automation
• Wireless sensor networks
• Wearable electronics
• Industrial control systems
• Robotics and drones
• Prototyping and educational projects

The ESP32 has 38 pins in total, with the following key pin assignments:

Note: Some pins have specific functions or limitations. Refer to the ESP32 datasheet for detailed pin multiplexing information.

1. Powering the ESP32:

   • Connect the ESP32 to a 5 V USB power source or provide 3.3 V directly to the 3V3 pin.
   • Ensure the power supply can provide sufficient current (at least 500 mA).

2. Programming the ESP32:

   • Install the CH340 driver on your computer to enable USB communication.
   • Use the Arduino IDE or Espressif's ESP-IDF for programming.
   • Select the correct board (e.g., "ESP32 Dev Module") and COM port in the IDE.

3. Connecting Peripherals:

   • Use GPIO pins for digital input/output, ADC pins for analog input, and DAC pins for analog output.
   • Ensure peripherals operate at 3.3 V logic levels to avoid damaging the ESP32.

4. Uploading Code:

   • Press and hold the "BOOT" button while uploading code to enter programming mode.
   • Release the button once the upload begins.

• Voltage Levels: The ESP32 operates at 3.3 V. Avoid applying 5 V to GPIO pins.
• Boot Mode: GPIO0 must be pulled low during boot to enter programming mode.
• Power Supply: Use a stable power source to prevent unexpected resets or malfunctions.
• Wi-Fi and Bluetooth: Avoid placing the ESP32 near metal objects or enclosures that may interfere with wireless signals.

The following example demonstrates how to blink an LED connected to GPIO2 of the ESP32:

// Blink an LED connected to GPIO2 on the ESP32
// Ensure the LED's anode is connected to GPIO2 and cathode to GND

#define LED_PIN 2  // GPIO2 is commonly used for onboard LEDs

void setup() {
  pinMode(LED_PIN, OUTPUT);  // Set GPIO2 as an output pin
}

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

1. ESP32 Not Detected by Computer:

   • Ensure the CH340 driver is installed correctly.
   • Check the USB cable and port for proper connection.

2. Code Upload Fails:

   • Verify the correct board and COM port are selected in the IDE.
   • Hold the "BOOT" button during the upload process.

3. Wi-Fi Connection Issues:

   • Ensure the Wi-Fi credentials are correct.
   • Check for interference or weak signal strength.

4. Random Resets or Instability:

   • Use a stable power supply with sufficient current capacity.
   • Avoid using GPIO pins that conflict with boot mode.

Q: Can the ESP32 operate on battery power?
A: Yes, the ESP32 can be powered by a LiPo battery or other 3.3 V sources. Use a voltage regulator if necessary.

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

Q: Can I use the ESP32 with 5 V logic devices?
A: No, the ESP32 operates at 3.3 V logic levels. Use a level shifter for compatibility with 5 V devices.

Q: What is the maximum range of the ESP32's Wi-Fi?
A: The range depends on environmental factors but typically extends up to 100 meters in open space.