Ultrasonic Height Measurement System with I2C LCD & Arduino UNO

An embedded height measurement system developed for Biomedical Engineering applications. The system utilizes an HC-SR04 Ultrasonic Sensor to measure distance and calculates human/object height dynamically, displaying real-time results on a 16x2 I2C Liquid Crystal Display (LCD).

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📐 Working Principle

1. Distance Measurement: The HC-SR04 sensor emits a 40 kHz ultrasonic wave from TRIG_PIN. The echo pulse duration is measured at ECHO_PIN.

2. Speed of Sound Calculation: Using sound velocity in air (~0.0343 cm/µs):

   Distance (cm) = (Duration × 0.0343) / 2

3. Height Deduction: Knowing the fixed sensor height from the floor (SENSOR_HEIGHT = 30 cm):

   Height = SENSOR_HEIGHT - Distance

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🛠️ Hardware Components

• Arduino UNO Microcontroller Board
• HC-SR04 Ultrasonic Distance Sensor
• 16x2 LCD Display with I2C Backpack Module (PCF8574)
• Breadboard & Jumper Wires
• 5V Power Supply / USB Cable

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🔌 Circuit Pin Wiring Diagram

Component	Pin / Terminal	Arduino Pin
HC-SR04 Sensor	VCC	5V
	GND	GND
	Trig	Pin 9
	Echo	Pin 10
I2C LCD Display	VCC	5V
	GND	GND
	SDA	A4 (or SDA Pin)
	SCL	A5 (or SCL Pin)

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💻 Software Dependencies & Setup

1. Download and install the Arduino IDE.
2. Install the LiquidCrystal_I2C library via Arduino Library Manager (Sketch -> Include Library -> Manage Libraries...).
3. Connect the Arduino board to your PC via USB.
4. Upload HeightMeter.ino to your Arduino UNO.
5. Adjust the SENSOR_HEIGHT constant in the code according to your physical setup height in centimeters.

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📄 License

This project is licensed under the MIT License.