🎵 Ultrasonic Levitator - Acoustic Levitation System

Important Note: This repository contains the basic prototype version of the ultrasonic levitator. The advanced version (Version 2.0) with motorized conveyor belt and automated features was the actual award-winning model that earned the prizes mentioned below.

Award-winning high school science exhibition project demonstrating acoustic levitation using ultrasonic transducers

🌟 Project Highlights

This project showcases the fascinating physics of acoustic levitation - the ability to suspend objects in mid-air using nothing but sound waves! By creating precise standing wave patterns with ultrasonic transducers, small particles can be trapped and levitated against gravity.

🏆 Competition Results

• 🥇 1st Prize - State Level Science Exhibition
• 🥈 2nd Prize - Zonal Level Science Fair

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📺 Demonstration Videos

Main Demonstration

ultrasonic_levitator.mp4

Watch the complete levitation system in action

Close-up View

ultrasonic_levitator_closeup.mp4

Local Video Files

• 📹 Main Demo
• 🔍 Close-up View

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🔬 Scientific Principle

Acoustic Levitation Mechanism

Principle:
Uses intense sound wave radiation pressure to counteract gravity on small objects via nonlinear acoustic effects.

Core Process:

1. Standing Wave Generation
   Opposing ultrasonic transducers create interference patterns.

2. Stable Trapping
   Objects are trapped at pressure nodes (minimal acoustic pressure variation).

3. Force Balance
   Time-averaged radiation pressure (nonlinear Bernoulli effect) provides upward force equal to gravity.

4. Frequency Scaling
   Ultrasonic frequencies (e.g., 40 kHz) match wavelength to object size (λ ≈ 8.6 mm for mm-scale particles), not object resonance.

Key Physics:

• Standing Wave Interference
• Acoustic Radiation Pressure
• Gor'kov Potential Theory
• Wavelength-Object Size Matching

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🛠️ System Architecture

Hardware Components

Component	Purpose	Specifications
Arduino Uno	Signal Generation	40kHz via Timer1 interrupts
HC-SR04 Transducers	Ultrasonic Emission	40kHz piezoelectric elements
Power Supply	System Power	5V DC source
Support Framework	Alignment System	Manual positioning mechanism

Pin Connections

• Transducers: Connect to analog pins A0, A1, A2, A3, A4, A5
• Power: All transducers VCC to Arduino 5V
• Ground: All transducers GND to Arduino GND

Circuit Schematic

Circuit diagram showing the connection setup for ultrasonic transducers

Credit: Schematic reference from Edison Science Corner - was really helpful while building the project

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💻 Software Implementation

Precise Timer-Based Code

The system uses Timer1 interrupts for precise 40kHz frequency generation. This provides more accurate timing than the basic tone() function:

byte TP = 0b10101010; // Every other port receives the inverted signal

void setup() {
  DDRC = 0b11111111; // Set all analog ports to be outputs
  
  // Initialize Timer1
  noInterrupts(); // Disable interrupts
  
  TCCR1A = 0;
  TCCR1B = 0;
  TCNT1 = 0;
  OCR1A = 200; // Set compare register (16MHz / 200 = 80kHz square wave -> 40kHz full wave)
  
  TCCR1B |= (1 << WGM12); // CTC mode
  TCCR1B |= (1 << CS10); // Set prescaler to 1 ==> no prescaling
  TIMSK1 |= (1 << OCIE1A); // Enable compare timer interrupt
  
  interrupts(); // Enable interrupts
}

ISR(TIMER1_COMPA_vect) {
  PORTC = TP; // Send the value of TP to the outputs
  TP = ~TP; // Invert TP for the next run
}

void loop() {
  // Nothing left to do here :)
}

Code Files

• code/prototype_code.ino - Complete levitation code

Key Features

• Precise Timing: Uses hardware Timer1 for exact 40kHz generation
• Multiple Outputs: Can drive transducers on analog pins A0-A5
• Efficient: Interrupt-based operation with minimal CPU overhead

Code Reference: Timer-based implementation adapted from Edison Science Corner - was really helpful while building the project

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🚀 Project Versions

Version 1.0 - Basic Prototype ✅

Status: Completed and Demonstrated

Basic prototype setup showing the ultrasonic levitation system

Features:

• Dual transducer setup using salvaged HC-SR04 elements
• Arduino-based 40kHz signal generation
• Manual alignment system
• Successfully levitates thermocol/foam particles

Demonstration: Available in project videos

Version 2.0 - Advanced System 🏆

Status: Award-Winning Model (State and zonal level)

Enhanced Features:

• Integrated motorized conveyor belt system
• L298N motor driver for precise movement control
• Automated particle feeding mechanism
• Enhanced stability and precision

Unfortunately, I lost the videos and documentation for Version 2.0 during a phone data transfer

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📊 Technical Specifications

Performance Metrics

• Operating Frequency: 40 kHz ± 100 Hz
• Maximum Levitation Height: 5-8 mm
• Particle Size Range: 0.5-3 mm diameter
• Power Consumption: < 2W
• Setup Time: < 5 minutes

Supported Materials

• ✅ Thermocol/Styrofoam particles
• ✅ Small plastic beads
• ✅ Lightweight foam pieces
• ✅ Paper fragments
• ❌ Metal objects (too dense)
• ❌ Water droplets (surface tension)

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🏗️ Quick Build Instructions

Prerequisites

• Arduino Uno
• HC-SR04 ultrasonic sensor modules (for transducers)
• Jumper wires and breadboard
• Arduino IDE installed

Simple Setup Steps

1. Extract Transducers

   • Carefully remove ultrasonic transducers from HC-SR04 modules
   • Keep the original wiring intact

2. Make Connections

   • Connect transducers to Arduino analog pins A0-A5
   • Connect VCC to Arduino 5V
   • Connect GND to Arduino GND

3. Upload Code

   • Download prototype_code.ino from the /code/ folder
   • Upload to Arduino using Arduino IDE

4. Physical Setup

   • Position two transducers face-to-face, about 2-3cm apart
   • Ensure they are perfectly aligned
   • Place small thermocol particles between them

5. Test

   • Power on Arduino
   • Observe levitation of small particles!

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📄 License

This project is open source and available under the MIT License.