How to Use ESP8266 NodeMCU custom size: Examples, Pinouts, and Specs

The ESP8266 NodeMCU is a versatile Wi-Fi microcontroller board based on the ESP8266 chip, designed specifically for Internet of Things (IoT) applications. It combines a powerful microcontroller with built-in Wi-Fi capabilities, making it ideal for projects requiring wireless connectivity. The custom size variant allows for tailored dimensions to fit specific project requirements, offering flexibility for compact or space-constrained designs.

• Home automation systems (e.g., smart lights, thermostats)
• IoT sensor networks
• Wireless data logging and monitoring
• Remote control of devices via mobile apps or web interfaces
• Prototyping and development of connected devices

• Microcontroller: ESP8266 (Tensilica L106 32-bit processor)
• Clock Speed: 80 MHz (can be overclocked to 160 MHz)
• Flash Memory: 4 MB (customizable in some variants)
• Operating Voltage: 3.3V
• Input Voltage: 4.5V–10V (via VIN pin) or 5V (via USB)
• Wi-Fi Standards: 802.11 b/g/n
• GPIO Pins: Up to 11 (configurable)
• Communication Protocols: UART, SPI, I2C, PWM
• USB Interface: Built-in CP2102 or CH340 USB-to-serial converter
• Power Consumption: ~70 mA (active), ~10 µA (deep sleep mode)
• Dimensions: Customizable to fit project needs

The ESP8266 NodeMCU custom size variant typically includes the following pinout:

Note: The number of GPIO pins available may vary depending on the custom size configuration.

1. Powering the Board:

   • Use the USB port for development and programming.
   • For standalone operation, supply 4.5V–10V to the VIN pin or 3.3V to the 3V3 pin.

2. Connecting to Wi-Fi:

   • Use the built-in Wi-Fi module to connect to a network. Ensure the SSID and password are correctly configured in your code.

3. Programming:

   • Install the Arduino IDE and add the ESP8266 board package.
   • Select "NodeMCU 1.0 (ESP-12E Module)" as the board type.
   • Connect the board to your computer via USB and upload your code.

4. GPIO Usage:

   • Configure GPIO pins as input or output in your code.
   • Avoid using GPIO0, GPIO2, and GPIO15 for critical functions, as they affect the boot process.

• Voltage Levels: Ensure all connected components operate at 3.3V logic levels. Use level shifters if interfacing with 5V devices.
• Deep Sleep Mode: Use deep sleep mode to conserve power in battery-operated projects.
• Custom Size: Verify the pinout and dimensions of your custom-sized board before designing your PCB or enclosure.
• Boot Mode: Ensure GPIO0 is HIGH during boot to avoid entering flash mode unintentionally.

The following example demonstrates how to connect the ESP8266 NodeMCU to a Wi-Fi network and control the built-in LED:

#include <ESP8266WiFi.h>

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

void setup() {
  Serial.begin(115200); // Initialize serial communication
  pinMode(LED_BUILTIN, OUTPUT); // Set built-in LED pin as output

  // Connect to Wi-Fi
  Serial.print("Connecting to Wi-Fi");
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWi-Fi connected!");
}

void loop() {
  // Blink the built-in LED
  digitalWrite(LED_BUILTIN, LOW); // Turn LED on
  delay(1000); // Wait for 1 second
  digitalWrite(LED_BUILTIN, HIGH); // Turn LED off
  delay(1000); // Wait for 1 second
}

1. Board Not Detected by Computer:

   • Ensure the correct USB driver (CP2102 or CH340) is installed.
   • Try a different USB cable or port.

2. Wi-Fi Connection Fails:

   • Double-check the SSID and password in your code.
   • Ensure the router is within range and supports 2.4 GHz Wi-Fi (ESP8266 does not support 5 GHz).

3. Code Upload Fails:

   • Verify the correct board and port are selected in the Arduino IDE.
   • Press and hold the FLASH button on the board while uploading.

4. GPIO Pin Issues:

   • Avoid using GPIO0, GPIO2, and GPIO15 for critical functions, as they affect the boot process.
   • Check for conflicting pin assignments in your code.

• Can I use the ESP8266 NodeMCU with 5V sensors?

  • No, the ESP8266 operates at 3.3V logic levels. Use a level shifter for 5V sensors.

• What is the maximum range of the Wi-Fi module?

  • The range is approximately 30 meters indoors and 100 meters outdoors, depending on obstacles and interference.

• How do I enable deep sleep mode?

  • Connect GPIO16 to the RESET pin and use the ESP.deepSleep() function in your code.

• Can I customize the board size and pinout?

  • Yes, custom-sized variants are available. Contact your supplier for details.