Budget-friendly security using Arduino and ultrasonic sensors. Instantly detects movement within set range, triggering visual and auditory alerts. Costs under $50. Making advanced security accessible!
Inspiration: We wanted to create an accessible security solution that anyone could build and customize. Many commercial alarm systems are expensive and complex, putting effective perimeter monitoring out of reach for students, hobbyists, and budget-conscious individuals. We saw an opportunity to use affordable Arduino components to democratize security technology and show how simple sensors can provide real-time protection.
What it does: ProxGuard monitors a defined perimeter using ultrasonic distance sensing. When an object or person breaches the set detection range, the system provides immediate multi-level alerts: LEDs indicate proximity levels (green for safe, yellow for caution, red for breach), while dual buzzers (passive and active) emit audible warnings. The system continuously monitors the area in real-time, making it ideal for home security, parking assistance, warehouse safety zones, or equipment protection.
How we built it: We assembled ProxGuard using an Arduino Uno as the central controller, an ultrasonic sensor for distance measurement, three LEDs with current-limiting resistors for visual feedback, and both passive and active buzzers for auditory alerts. All components were mounted on a breadboard and connected with jumper wires following our hand-drawn hookup diagram. Connor developed the Arduino code to read sensor data, process distance calculations, and trigger appropriate alerts based on configurable thresholds.
Challenges we ran into: Calibrating the ultrasonic sensor for consistent readings was difficult. We had to account for environmental factors and sensor positioning to minimize false triggers. Coordinating the timing between LED indicators and buzzer alerts required careful programming to ensure alerts were clear and not overwhelming. We also had to troubleshoot wiring issues on the breadboard, as a single loose connection could disable the entire system.
Accomplishments that we're proud of: We successfully created a fully functional proximity detection system from scratch using affordable components (under $50 total). Our multi-level alert system effectively communicates different threat levels through coordinated visual and auditory feedback. The system is reliable, responsive, and easily customizable. Users can adjust detection ranges and alert patterns by simply modifying the code. We're especially proud of the versatility of our design beyond security applications, ProxGuard can be repurposed as an air piano (where hand movements trigger different musical notes).
What we learned: This project deepened our understanding of sensor integration, real-time data processing, and Arduino programming. We learned how ultrasonic sensors measure distance using sound waves and how to convert raw sensor data into actionable alerts. The experience reinforced the importance of systematic debugging and testing small errors in wiring or code logic can cascade into system failures. We also gained valuable experience in hardware-software integration, project documentation, and presenting technical concepts to diverse audiences. Most importantly, we learned that effective engineering solutions don't require expensive components. Creativity and problem-solving matter more than budget.
What's next for ProxGuard: Distance Sensor Security: We plan to enhance ProxGuard with budget-friendly upgrades that expand its functionality. Adding an inexpensive LCD screen would display real-time distance readings and breach status, making the system more informative without checking the Arduino serial monitor. We can create a simple mobile or desktop app that connects to ProxGuard and sends push notifications when breaches are detected. The app would allow users to monitor their space remotely and receive instant alerts on their phones. We'd also like to add a simple keypad for users to easily adjust detection thresholds easily, and potentially incorporate a buzzer pattern selector to customize alarm sounds. These improvements maintain our core philosophy of keeping the system accessible and affordable while significantly enhancing user experience and practical functionality for real-world security applications.
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