Park Sensor

An Arduino-based ultrasonic distance sensing system with visual and auditory feedback, designed as a parking assistance prototype.

Overview

This project implements a real-time distance measurement system using an HC-SR04 ultrasonic sensor. The system provides multi-modal feedback through an RGB LED, active buzzer, and 16x2 LCD display, making it suitable for parking assistance or general proximity detection applications.

Features

• Real-time distance measurement with HC-SR04 ultrasonic sensor (0-400cm range)
• RGB LED feedback with color transitions based on proximity:
  • Red: Safe distance (>30cm)
  • Red→Green gradient: Approaching (5-30cm)
  • Green: Critical proximity (<5cm)
• Variable buzzer alerts with frequency and interval changes based on distance
• LCD display showing current distance in centimeters
• Toggle switch for system on/off control with debouncing
• Low power standby mode when system is disabled

Hardware Requirements

• Arduino Uno
• HC-SR04 Ultrasonic Sensor
• 16x2 LCD Display (HD44780 compatible)
• RGB LED (common cathode)
• Active/Passive Buzzer
• Push Button
• 10kΩ Potentiometer (for LCD contrast)
• 3× 220Ω Resistors (for RGB LED)
• Jumper wires
• Breadboard

Pin Configuration

Component	Arduino Pin
Button	A0 (INPUT_PULLUP)
Buzzer	D2
Sensor TRIG	D3
Sensor ECHO	D4
RGB LED - Red	D5 (PWM)
RGB LED - Green	D6 (PWM)
RGB LED - Blue	D7 (PWM)
LCD D7	D8
LCD D6	D9 (PWM)
LCD D5	D10 (PWM)
LCD D4	D11 (PWM)
LCD E	D12
LCD RS	D13

LCD Wiring

• VSS → GND
• VDD → 5V
• V0 → Potentiometer (contrast)
• RS → D13
• RW → GND
• E → D12
• D4-D7 → D11, D10, D9, D8
• A (backlight) → 5V
• K (backlight) → GND

RGB LED Wiring

• Common cathode (longest pin) → GND
• Red → 220Ω → D5
• Green → 220Ω → D6
• Blue → 220Ω → D7

Distance-Based Behavior

Range	LED Color	Buzzer Frequency	Blink/Beep Interval
0-5cm	Green	1500 Hz	100ms (Fast)
5-30cm	Red→Green gradient	1000 Hz	300ms (Medium)
>30cm	Red	600 Hz	600ms (Slow)

Installation

1. Clone this repository:

git clone https://github.com/yourusername/park_sensor.git
cd park_sensor

2. Open park_sensor.ino in Arduino IDE

3. Install required library:

   • LiquidCrystal (usually pre-installed with Arduino IDE)

4. Connect hardware according to pin configuration

5. Upload to Arduino Uno

Usage

1. Power on the Arduino
2. Press the button to toggle the system on/off
3. When active, the system will:
   • Display distance on LCD
   • Change LED color based on proximity
   • Emit variable frequency beeps
4. Press button again to enter standby mode (white LED)

Code Structure

• setup(): Initializes pins, LCD, and displays startup message
• loop(): Main control flow with button debouncing, sensor reading, and feedback logic
• Debounce delay: 50ms for stable button operation
• Distance calculation: duration / 58 for centimeters

Technical Notes

• Uses INPUT_PULLUP for button, eliminating need for external pull-up resistor
• PWM on LED pins enables smooth color transitions via analogWrite()
• Ultrasonic sensor timeout set to 30ms (~5m maximum range)
• LCD operates in 4-bit mode to conserve pins

Future Improvements

• Add EEPROM storage for distance thresholds
• Implement multiple sensor array for wider coverage
• Add serial output for data logging
• Customizable alert patterns

License

MIT License - feel free to modify and use for your projects.

Author

Built as a learning project for Arduino-based sensor systems.