Introduction#

Have you ever thought about how parking gates open automatically when a car approaches?
Well.. in this project, I set out to build a smart parking gate using an Arduino UNO R3, a servo motor, and an ultrasonic sensor.
The idea is simple: detect when a car (or an object.. anything basically) is near, and automatically lift the gate.

It’s a small but fun automation project that combines electronics, coding, and real-world application!

What You’ll Need#

• Arduino UNO (or any microcontroller)
• Ultrasonic sensor (HC-SR04) or IR sensor
• Servo motor (to act as the gate arm)
• Breadboard and jumper wires
• Power supply (USB or battery pack)
• (Optional) LED lights & an LCD display for additional signals

How It Works#

Simple diagram of the project, made in Wokwi

1. First, the ultrasonic sensor continuously measures the distance in front of the gate. To get this reading accurately, I averaged multiple samples from the ultrasonic sensor:

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float getAverageDistance() {
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  long total = 0;
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  const int samples = 5;
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  for (int i = 0; i < samples; i++) {
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    digitalWrite(PIN_TRIG, LOW);
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    delayMicroseconds(2);
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    digitalWrite(PIN_TRIG, HIGH);
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    delayMicroseconds(10);
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    digitalWrite(PIN_TRIG, LOW);
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    long duration = pulseIn(PIN_ECHO, HIGH, 30000);
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    float distance = duration * 0.034 / 2;
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    if (distance > 0 && distance < 400) {
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      total += distance;
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    } else {
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      total += 400; // assume max range if error
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    }
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    delay(10);
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  }
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  return total / samples;
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}

This helps filter out noisy readings and ensures the servo only reacts when a car is actually present.

2. When a car comes within a set distance (e.g., 10 cm), the Arduino sends a signal to the servo motor and other indicators (in here, I used a 16x2 LCD and 2 LEDs).

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if (jarak > 0 && jarak <= 10) {
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  palangServo.write(90); // open gate
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  digitalWrite(PIN_LED_R, LOW);
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  digitalWrite(PIN_LED_G, HIGH);
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  lcd.print("Status: Buka");
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  isOpen = true;
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  lastOpenTime = currentTime;
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}

The green LED turns on when the gate is open, while the red LED remains off.

3. After 2 seconds, the system closes the gate again:

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else {
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  palangServo.write(0); // close gate
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  digitalWrite(PIN_LED_R, HIGH);
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  digitalWrite(PIN_LED_G, LOW);
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  lcd.print("Status: Tutup");
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  isOpen = false;
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}

Here, the red LED turns on, indicating that the gate is closed.

4. (Optional, last step) LCD + RemoteXY connection and display.

I also experimented with adding a 16x2 LCD to display the distance and status, plus the RemoteXY app so I could monitor the gate from my phone over a Wi-Fi point (this requires an additional ESP8266 module).

Full Code#

The full code will be released on 17th of September.. 😉

The End!#

Thank you for reading this far into this first guide that I made, hopefully this can inspire you guys to build more awesome and usefull stuff for everyday activities!

Happy coding!