Arduino-Based Automatic Gate with PIR Sensor & Servo Motor

Hello and welcome back! In this project, we will learn how to make an automatic gate control system using Arduino. For this, I have mainly used a PIR motion sensor to detect motion. When motion is detected, an SG90 servo motor automatically opens and closes the gate. To indicate the gate status, I have used a traffic light module, which makes it easier to know whether the gate is open or closed.

This project is easy to build with just a few steps and requires a low budget, making it perfect for beginners. I used an Arduino Nano board, but you can use any other Arduino board that fits your needs. Also, you can modify it by adding a buzzer for sound alerts.

Ok, let’s do this project step by step. The required components are given below.

• Arduino Nano board x 1 — Our Store / Amazon 
• PIR sensor x 1  —  Our Store / Amazon
• Traffic light module x 1 — Our Store / Amazon
• Jumper wires —  Our Store / Amazon
• Servo motor x 1 — Our Store / Amazon 
• Breadboard — Our store / Amazon

Disclosure: These Amazon links are Affiliate links. As an Amazon Associate, I earn from qualifying purchases.

Step 1

Firstly, identify these components.

Step 2

Secondly, place the Arduino Nano board and the traffic light module onto the breadboard.

Step 3

Then, connect the traffic light module and PIR sensor to the Arduino board using the circuit diagram below.

Step 4

Next, calibrate the servo motor and connect it to the Arduino Nano board. Afterward, connect the Arduino board to the computer.

Step 5

Now, copy and paste the following program into the Arduino IDE. Then, adjust the servo motor values to match your servo motor’s position.

• Code and Circuit Diagram – Download

#include <Servo.h>

#define R 2  // Red LED (Motion Detected)
#define Y 3  // Yellow LED (Closing Warning)
#define G 4  // Green LED (Gate Open)
#define sensor 5  // PIR Sensor Input

Servo servo;

void setup() {
  Serial.begin(9600);
  pinMode(R, OUTPUT);
  pinMode(Y, OUTPUT);
  pinMode(G, OUTPUT);
  pinMode(sensor, INPUT);
  
  servo.attach(9);
  servo.write(110);  // Initial position (Closed)
}

// Function to move servo smoothly
void smoothServoMove(int start, int end, int stepDelay) {
  
  if (start < end) {
    for (int pos = start; pos <= end; pos++) {
      servo.write(pos);
      delay(stepDelay);
    }
  } else {
    for (int pos = start; pos >= end; pos--) {
      servo.write(pos);
      delay(stepDelay);
    }
  }
}

// Function to blink yellow LED before closing
void blinkWarningLED() {
  for (int i = 0; i < 5; i++) {
    digitalWrite(Y, HIGH);
    delay(300);
    digitalWrite(Y, LOW);
    delay(300);
  }
}

void loop() {
  bool value = digitalRead(sensor);
  Serial.println(value);

  if (value == HIGH) {
    delay(500); // Double-check motion to avoid false triggers
    if (digitalRead(sensor) == HIGH) {  
      digitalWrite(R, HIGH);  // Motion detected
      smoothServoMove(110, 180, 30);  // Open gate smoothly
      digitalWrite(G, HIGH);  // Gate is open
      digitalWrite(R, LOW);
      delay(3000);  // Keep gate open for 2 seconds
      
      digitalWrite(G, LOW);
      blinkWarningLED();  // Blink yellow LED before closing
      digitalWrite(R, HIGH);
      smoothServoMove(180, 110, 30);  // Close gate smoothly
      digitalWrite(R, LOW);
    }
  }
  delay(1000);
}

• Next, select the board and port, then click the upload button.

Step 6

Afterward, remove the USB cable and prepare the servo motor mount stand. For that, you can use the following sizes. I used a piece of foam board for this.

Step 7

Next, prepare the gate part using a piece of foam board. Then, I added a design to this part (lol).

Step 8

Now, install it on the servo horn. Finally, connect the external power supply to the system.

OK! You can now test this project using a Bluetooth-controlled car or a toy car. The full video guide is below. We hope to see you in the next project! Have a great day.

Troubleshooting tips

• Check the wiring.
• Adjust the PIR sensor sensitivity.
• Calibrate your servo motor.
• Enter the correct servo values.
• Select the correct board and port.
• Check the Power supply.

Arduino Based Automatic Gate with PIR Sensor & Servo Motor