How to Use NODEMCU-32S : Examples, Pinouts, and Specs

The NODEMCU-32S is a low-cost, open-source IoT platform built around the powerful ESP32 microcontroller. It is designed for developing connected devices and features integrated Wi-Fi and Bluetooth capabilities, making it an excellent choice for IoT applications. The board includes a USB interface for programming and power, a variety of GPIO pins for interfacing with sensors and actuators, and supports programming in both Lua script and the Arduino IDE.

• Home automation systems
• Smart sensors and IoT devices
• Wireless data logging
• Remote monitoring and control
• Prototyping connected devices

• Microcontroller: ESP32 (dual-core, 32-bit LX6 processor)
• Clock Speed: Up to 240 MHz
• Flash Memory: 4 MB
• SRAM: 520 KB
• Wi-Fi: 802.11 b/g/n
• Bluetooth: v4.2 BR/EDR and BLE
• Operating Voltage: 3.3V
• Input Voltage (via USB): 5V
• GPIO Pins: 30 (including ADC, DAC, PWM, I2C, SPI, UART)
• ADC Channels: 18 (12-bit resolution)
• DAC Channels: 2 (8-bit resolution)
• USB Interface: Micro-USB
• Dimensions: 58mm x 31mm

The NODEMCU-32S has a total of 30 GPIO pins, each with multiple functions. Below is a summary of the pin configuration:

1. Powering the Board:

   • Connect the board to your computer or a USB power source using a Micro-USB cable.
   • Alternatively, supply 5V to the VIN pin and connect GND to ground.

2. Programming the Board:

   • Install the Arduino IDE and add the ESP32 board support package.
   • Select "NodeMCU-32S" as the board in the Arduino IDE.
   • Write your code and upload it to the board via the USB connection.

3. 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 NODEMCU-32S.

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

// Define the GPIO pin where the LED is connected
const int ledPin = 2;

void setup() {
  // Set the LED pin as an output
  pinMode(ledPin, OUTPUT);
}

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

  // Turn the LED off
  digitalWrite(ledPin, LOW);
  delay(1000); // Wait for 1 second
}

• Avoid applying voltages higher than 3.3V to the GPIO pins to prevent damage.
• Use level shifters if interfacing with 5V devices.
• Ensure proper grounding when connecting external components.
• Use pull-up or pull-down resistors as needed for input pins.
• Avoid powering high-current devices directly from the GPIO pins.

1. The board is not detected by the computer:

   • Ensure the USB cable is functional and supports data transfer.
   • Install the correct USB-to-serial driver for the NODEMCU-32S.

2. Code upload fails:

   • Check that the correct board and COM port are selected in the Arduino IDE.
   • Press and hold the "BOOT" button on the board while uploading the code.

3. Wi-Fi connection issues:

   • Verify the SSID and password in your code.
   • Ensure the Wi-Fi network is within range and operational.

4. GPIO pins not working as expected:

   • Double-check the pin configuration in your code.
   • Ensure no conflicting peripherals are using the same pins.

• Can I power the NODEMCU-32S with a battery?
  Yes, you can use a 3.7V LiPo battery connected to the VIN and GND pins.

• What is the maximum current the GPIO pins can source/sink?
  Each GPIO pin can source/sink up to 12mA safely.

• Can I use the NODEMCU-32S with MicroPython?
  Yes, the NODEMCU-32S supports MicroPython, but you need to flash the MicroPython firmware first.