How to Use NMCU-ESP32 : Examples, Pinouts, and Specs

The NMCU-ESP32, manufactured by na ich, is a versatile microcontroller unit (MCU) based on the ESP32 chip. It is equipped with built-in Wi-Fi and Bluetooth capabilities, making it an ideal choice for Internet of Things (IoT) applications. The NMCU-ESP32 offers robust processing power, multiple GPIO pins, analog-to-digital converters (ADCs), and support for various communication protocols, enabling seamless integration into a wide range of projects.

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

The NMCU-ESP32 is packed with features that make it a powerful and flexible component for embedded systems. Below are its key technical specifications:

The NMCU-ESP32 typically features a 38-pin layout. Below is a table of the most commonly used pins and their functions:

Note: The exact pinout may vary depending on the specific NMCU-ESP32 board model. Always refer to the datasheet or schematic for your board.

1. Powering the Board:
   • Use a USB cable to supply 5V via the micro-USB port.
   • Alternatively, provide 3.3V directly to the 3V3 pin or 5V to the VIN pin.
2. Connecting Peripherals:
   • Use the GPIO pins to connect sensors, actuators, or other peripherals.
   • Ensure that the voltage levels of connected devices are compatible with the 3.3V logic of the NMCU-ESP32.
3. Programming the Board:
   • Install the Arduino IDE or ESP-IDF (Espressif IoT Development Framework).
   • Select the appropriate board and port in the IDE.
   • Write and upload your code to the NMCU-ESP32 via the USB connection.

• Voltage Levels: The GPIO pins operate at 3.3V. Avoid applying 5V directly to the pins to prevent damage.
• Boot Mode: To enter bootloader mode for programming, hold the IO0 pin low while resetting the board.
• Power Supply: Ensure a stable power supply to avoid unexpected resets or malfunctions.
• Wi-Fi and Bluetooth: Avoid placing the board near metal objects or enclosures that may interfere with wireless signals.

Below is an example of how to use the NMCU-ESP32 to blink an LED connected to GPIO2:

// Example: Blink an LED on GPIO2 of the NMCU-ESP32

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

void setup() {
  // Set 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: Ensure that the LED is connected to GPIO2 with a current-limiting resistor (e.g., 220 ohms) to prevent damage.

1. The board is not detected by the computer:

   • Ensure the USB cable is functional and supports data transfer.
   • Install the necessary USB-to-serial drivers for the NMCU-ESP32.

2. Wi-Fi connection fails:

   • Verify the SSID and password in your code.
   • Check for interference or weak signal strength.

3. The board does not power on:

   • Confirm that the power supply is within the acceptable voltage range.
   • Check for loose connections or damaged components.

4. Code upload fails:

   • Ensure the correct board and port are selected in the IDE.
   • Hold the IO0 pin low while resetting the board to enter bootloader mode.

Q: Can the NMCU-ESP32 operate on battery power?
A: Yes, the board can be powered by a LiPo battery or other 3.3V/5V sources. Ensure proper voltage regulation.

Q: How many devices can connect to the NMCU-ESP32 via Bluetooth?
A: The ESP32 supports up to 7 simultaneous Bluetooth connections in classic mode.

Q: Can I use the NMCU-ESP32 with MicroPython?
A: Yes, the NMCU-ESP32 is compatible with MicroPython. Flash the MicroPython firmware to get started.

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

By following this documentation, you can effectively integrate the NMCU-ESP32 into your projects and troubleshoot common issues with ease.