Barrier Gate 3.0

Note

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Kit purchase

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Looking for parts? Check out our all-in-one kits below — packed with components, beginner-friendly guides, and tons of fun.

Name	Includes Arduino board	PURCHASE LINK
Ultimate Sensor Kit	Arduino Uno R4 Minima	BUY
Elite Explorer Kit	Arduino Uno R4 WiFi	BUY
3 in 1 Ultimate Starter Kit	Arduino Uno R4 Minima	BUY
Universal Maker Sensor Kit	×	BUY

Course Introduction

In this lesson, you’ll use a button, a traffic light LED module, and a servo motor with the Arduino to simulate a manual barrier gate system.

When the button is pressed, the red light turns off, the green light turns on, and the gate opens briefly to let a car pass.

Note

If this is your first time working with an Arduino project, we recommend downloading and reviewing the basic materials first.

• 1.1 Install Arduino IDE(Important)

• 1.2 Introduce of Arduino IDE

Required Components

In this project, we need the following components:

SN	COMPONENT INTRODUCTION	QUANTITY	PURCHASE LINK
1	Arduino UNO R4 Minima/Arduino UNO R4 WIFI	1	BUY
2	USB Type-C cable	1
3	Breadboard	1	BUY
4	Wires	Several	BUY
5	Button	1	BUY
6	Digital Servo Motor	1	BUY
7	LED	4	BUY
8	1kΩ resistor	4	BUY

Wiring

Common Connections:

• LED

  • Connect the LEDs cathode to the negative power bus on the breadboard, and the LEDs anode to a 1kΩ resistor then to 3, 4 on the Arduino.

• Digital Servo Motor

  • Connect to breadboard’s positive power bus.

  • Connect to breadboard’s negative power bus.

  • Connect to 11 on the Arduino.

• Button

  • Connect to breadboard’s negative power bus.

  • Connect to 2 on the Arduino.

Writing the Code

Note

• You can copy this code into Arduino IDE.

• Don’t forget to select the board(Arduino UNO R4 Minima/WIFI) and the correct port before clicking the Upload button.

#include <Servo.h>

const int buttonPin = 2;     // Button connected to digital pin 2
const int greenLed  = 3;     // Green LED connected to digital pin 3
const int redLed    = 4;     // Red LED connected to digital pin 4
const int servoPin  = 12;    // Servo signal connected to digital pin 12

Servo barrierServo;

void setup() {
  pinMode(buttonPin, INPUT_PULLUP);  // Enable internal pull-up on button pin
  pinMode(greenLed,  OUTPUT);
  pinMode(redLed,    OUTPUT);

  barrierServo.attach(servoPin);     // Attach servo to pin 12
  barrierServo.write(0);             // Start with barrier closed (0°)

  digitalWrite(redLed,   HIGH);      // Turn on red LED initially
  digitalWrite(greenLed, LOW);       // Turn off green LED initially

  Serial.begin(9600);                // For debugging
}

void loop() {
  // Check if button is pressed (active LOW)
  if (digitalRead(buttonPin) == LOW) {
    Serial.println("Button pressed: Opening barrier");

    digitalWrite(redLed,   LOW);      // Turn off red LED
    digitalWrite(greenLed, HIGH);     // Turn on green LED
    barrierServo.write(90);           // Raise barrier to 90°
    delay(2000);                      // Wait for 2 seconds

    barrierServo.write(0);            // Lower barrier back to 0°
    digitalWrite(greenLed, LOW);      // Turn off green LED
    digitalWrite(redLed,   HIGH);     // Turn on red LED
  }

  delay(100); // Short delay to debounce
}