NodeMCU8266 Digital Read (Push Button)

Detecting Push Button State with NodeMCU ESP8266

Introduction

In this tutorial, we'll learn how to detect the state of a push button using the NodeMCU ESP8266 development board. Digital inputs like push buttons are fundamental in electronics and IoT projects, allowing us to trigger actions based on user input.

What We Will Learn in This Section

• Setting up the NodeMCU ESP8266 for digital input.
• Writing code in Arduino IDE to read the state of a push button.
• Printing button state ("Pressed" or "Released") to the serial monitor.

Why Is This Lesson Important to You?

Understanding digital inputs and how to interface them with microcontrollers like the NodeMCU opens up possibilities for various projects:

• Building interactive IoT devices.
• Creating user interfaces with physical buttons.
• Implementing control mechanisms based on user input.

Components List

1. NodeMCU ESP8266 Development Board - Link to Amazon
2. Push Button Switch
3. Jumper Wires
4. Computer with Arduino IDE installed
5. Micro USB Cable - Link to Amazon

Circuit Diagram (With Connection)

• Connect one leg of the push button to GPIO 16 (D0) of the NodeMCU.
• Connect the other leg of the push button to ground (GND) of the NodeMCU using a jumper wire.

Code

void setup() {
  pinMode(16, INPUT);  // Set GPIO 16 (D0) as input
  Serial.begin(9600);  // Initialize serial communication
}

void loop() {
  int buttonState = digitalRead(16);  // Read the state of GPIO 16
  
  if (buttonState == LOW) {
    Serial.println("Button Pressed");  // Print message when button is pressed
  } else {
    Serial.println("Button Released");  // Print message when button is released
  }
  
  delay(1000);  // Delay for debounce and to avoid serial output flooding
}

Code Explanation

• void setup(): This function runs once when the NodeMCU starts up. It sets up GPIO 16 as an input pin using pinMode() and initializes serial communication at a baud rate of 9600 using Serial.begin().

• void loop(): This function runs repeatedly after setup() completes. It reads the state of GPIO 16 using digitalRead() and stores it in buttonState.

• if (buttonState == LOW): Checks if the button connected to GPIO 16 is pressed (LOW state).

• Serial.println("Button Pressed");: Prints "Button Pressed" to the serial monitor if the button is pressed.

• else: Executes when the button is released (HIGH state).

• Serial.println("Button Released");: Prints "Button Released" to the serial monitor if the button is released.

• delay(1000);: Adds a 1-second delay to debounce the button and prevent rapid serial output.

Final Notes

This tutorial demonstrated a basic example of reading digital input using the NodeMCU ESP8266 and Arduino IDE. Experiment with different GPIO pins and expand this concept to include more complex projects involving digital inputs and outputs. Understanding how to handle user inputs is crucial for developing interactive IoT applications.

Stay tuned for more tutorials and projects on NodeMCU and IoT development!