IDPL - 5: Integration of Actuators with NodeMCU

IDPL - 5: Integration of Actuators with NodeMCU (Servo Motor)

Objective

To interface and control a servo motor and a Buzzer independently using NodeMCU ESP8266.

Required Components

NodeMCU ESP8266
Servo motor
LED Bar
External 5 V power supply

Part A: Servo Motor Interfacing

Objective

To interface a servo motor with NodeMCU ESP8266 and control its angular position using a programmed control signal.

Circuit Diagram

Servo Motor Pin Connections

Servo Motor Pin / Connection	Connection Details
Signal / Data	Connect to NodeMCU D5 (GPIO14)
GND	Connect to NodeMCU GND
VCC	Connect to the positive (+) terminal of the external 5 V power supply
External Power Supply GND	Connect to NodeMCU GND to provide a common ground
Power Adapter DC Jack	Connect the DC jack pin of the adapter to the DC jack provided on the kit

Important: Use the external 5 V supply to power the servo motor. The NodeMCU GND and external power-supply GND must be connected together to provide a common reference for the servo control signal.

Working Principle

A servo motor is an actuator that can rotate its shaft to a specified angular position.

The NodeMCU generates a PWM-based control signal on D5. The servo interprets this signal and moves its shaft to the corresponding angular position.

In this experiment, the servo is programmed to move as per the angle given by the user via serial monitor. The user can specify the angle between 0° to 180°.

Experiment Code for Servo Motor

// © 2026, Cognifront. Member of The IoT Kits Family.

// Experiment: Servo Motor Interfacing with NodeMCU
// Board: NodeMCU ESP8266

#include <Servo.h>

// Create servo object
Servo myServo;

// Servo signal connected to D5
#define SERVO_PIN D5

void setup() {

  // Start Serial Monitor
  Serial.begin(9600);

  // Attach servo with pulse range
  myServo.attach(SERVO_PIN, 500, 2400);

  // Set initial position
  myServo.write(0);

  Serial.println("SG90 Servo Control");
  Serial.println("Enter angle (0-180):");
}

void loop() {

  // Check if a value is entered in Serial Monitor
  if (Serial.available() > 0) {

    // Read the angle
    int angle = Serial.parseInt();

    // Make sure angle is within range
    if (angle >= 0 && angle <= 180) {

      // Move servo
      myServo.write(angle);

      // Display current angle
      Serial.print("Servo moved to: ");
      Serial.print(angle);
      Serial.println(" degrees");

    } else {
      Serial.println("Enter an angle between 0 and 180.");
    }

    // Clear remaining Serial data
    while (Serial.available() > 0) {
      Serial.read();
    }
  }
}

Important Note

The program uses the Servo library.

Try compiling the code normally without edit first, if servo moves as expected no need for external library as while we install the NodeMCU in Arduino IDE, some basics libraries we get preinstalled, one of them is Servo.h For ESP8266 boards, install the ESP8266Servo library if the standard Servo library is not available or does not compile correctly with the selected NodeMCU board.

Observation

The servo moves to as per the ange specified by the user
The servo movement is controlled by the NodeMCU through D5.

Result

The servo motor was successfully interfaced with NodeMCU ESP8266 and controlled to move to different angular positions.

Conclusion

This experiment demonstrates the interfacing and control of a servo motor using NodeMCU ESP8266. The NodeMCU generates the required control signal and the servo motor responds by moving to the programmed angular positions.

Part B: LED Interfacing

Objective

To interface a LED with NodeMCU ESP8266 and control the LED using a digital output signal.

Circuit Diagram

Working Principle

A LED is an electronic device used to produce an audible sound when an electrical signal is applied to it.

The NodeMCU controls the LED through D1 using a digital output signal.

When the output signal is HIGH, the LED is activated. When the output signal is LOW, the LED is deactivated.

In this experiment, the LED is programmed to:

Turn ON for 2 seconds.
Turn OFF for 2 seconds.
Repeat continuously.

LED Pin Connections

LED Connection	Connection Details
Data	Connect to NodeMCU D1
GND	Connect to NodeMCU GND

Experiment Code for LED

// © 2026, Cognifront. Member of The IoT Kits Family.

// Experiment: LED Interfacing with NodeMCU
// Board: NodeMCU ESP8266

int LEDPin = D1;

void setup() {

  // Set LED pin as output
  pinMode(LEDPin, OUTPUT);

  // Turn LED OFF initially
  digitalWrite(LEDPin, LOW);
}

void loop() {

  // Turn LED ON
  digitalWrite(LEDPin, HIGH);
  delay(2000);

  // Turn LED OFF
  digitalWrite(LEDPin, LOW);
  delay(2000);
}

Testing the LED

Connect the LED Signal pin to D1.

Connect the LED GND pin to NodeMCU GND.

Connect the NodeMCU to the computer using the USB cable.

Select the NodeMCU board and the appropriate COM port in Arduino IDE.

Upload the program to the NodeMCU.

Observe the LED operation.

The LED should turn ON for approximately 2 seconds.

The LED should turn OFF for approximately 2 seconds.

The process repeats continuously.

Observation

The LED remains OFF initially.
The LED turns ON for approximately 2 seconds.
The LED turns OFF for approximately 2 seconds.
The LED continuously switches between ON and OFF states.

Result

The LED was successfully interfaced with NodeMCU ESP8266 and controlled using a digital output signal.

Conclusion

This experiment demonstrates the interfacing and digital control of a LED using NodeMCU ESP8266. The LED is controlled by the NodeMCU through D1 using a digital output signal.