Train Ramp

Note

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Kit purchase

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
Elite Explorer Kit	Arduino Uno R4 WiFi	BUY
3 in 1 Ultimate Starter Kit	Arduino Uno R4 Minima	BUY

Course Introduction

In this lesson, you’ll learn how to build an automatic railway crossing using two IR Sensor Modules and two servo motors.

When a train passes the first sensor, the barriers lower to block the road. After the train reaches the second sensor, the barriers rise again, simulating a real railway crossing system.

Note

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

Required Components

In this project, we need the following components:

SN	COMPONENT INTRODUCTION	QUANTITY	PURCHASE LINK
1	Arduino UNO R4 Minima	1	BUY
2	USB Type-C cable	1
3	Breadboard	1	BUY
4	Wires	Several	BUY
5	Digital Servo Motor	2	BUY
6	IR Obstacle Avoidance Sensor Module	2	BUY

Wiring

Common Connections:

Digital Servo Motor 1
- Connect to breadboard’s positive power bus.
- Connect to breadboard’s negative power bus.
- Connect to 9 on the Arduino.
Digital Servo Motor 2
- Connect to breadboard’s positive power bus.
- Connect to breadboard’s negative power bus.
- Connect to 10 on the Arduino.
IR Obstacle Avoidance Sensor Module 1
- OUT: Connect to 2 on the Arduino.
- GND: Connect to breadboard’s negative power bus.
- VCC: Connect to breadboard’s red power bus.
IR Obstacle Avoidance Sensor Module 2
- OUT: Connect to 3 on the Arduino.
- GND: Connect to breadboard’s negative power bus.
- VCC: Connect to breadboard’s red power bus.

Writing the Code

Note

You can copy this code into Arduino IDE.
Don’t forget to select the board(Arduino UNO R4 Minima) and the correct port before clicking the Upload button.

#include <Servo.h>

// IR sensor pins
const int IR_ENTRY_PIN = 2;
const int IR_EXIT_PIN = 3;

// Servo pins
const int SERVO_1_PIN = 9;
const int SERVO_2_PIN = 10;

// Servo angles
const int GATE_DOWN_ANGLE = 0;
const int GATE_UP_ANGLE = 90;

// Most IR obstacle sensors output LOW when an object is detected.
// If your sensor works the opposite way, change LOW to HIGH.
const int IR_DETECTED_STATE = LOW;

// Debounce
const unsigned long debounceDelay = 200;

Servo gateServo1;
Servo gateServo2;

bool gateOpen = false;

bool lastEntryState = HIGH;
bool lastExitState = HIGH;

unsigned long lastEntryTime = 0;
unsigned long lastExitTime = 0;

void setup() {
  pinMode(IR_ENTRY_PIN, INPUT);
  pinMode(IR_EXIT_PIN, INPUT);

  gateServo1.attach(SERVO_1_PIN);
  gateServo2.attach(SERVO_2_PIN);

  closeGate();
}

void loop() {
  bool currentEntryState = digitalRead(IR_ENTRY_PIN);
  bool currentExitState = digitalRead(IR_EXIT_PIN);

  unsigned long now = millis();

  // IR Sensor 1 detects the train: raise the barriers
  if (lastEntryState != IR_DETECTED_STATE && currentEntryState == IR_DETECTED_STATE) {
    if (now - lastEntryTime > debounceDelay) {
      openGate();
      lastEntryTime = now;
    }
  }

  // IR Sensor 2 detects the train: lower the barriers
  if (lastExitState != IR_DETECTED_STATE && currentExitState == IR_DETECTED_STATE) {
    if (now - lastExitTime > debounceDelay) {
      closeGate();
      lastExitTime = now;
    }
  }

  lastEntryState = currentEntryState;
  lastExitState = currentExitState;
}

void openGate() {
  gateOpen = true;
  gateServo1.write(GATE_UP_ANGLE);
  gateServo2.write(GATE_UP_ANGLE);
}

void closeGate() {
  gateOpen = false;
  gateServo1.write(GATE_DOWN_ANGLE);
  gateServo2.write(GATE_DOWN_ANGLE);
}