Multi-Stage Sensor-Activated Security System

Designed and built a prototype home security system that detects potential intrusions using multiple sensors and responds through a staged, automated deterrence sequence. The project focused on integrating sensing, actuation, and power systems into a cohesive electromechanical device.

Key Contributions

• Designed and implemented the mechanical and electrical architecture for a multi-stage response system

• Integrated motion (PIR) and acoustic sensors to enable reliable intrusion detection through sensor fusion

• Developed and wired a multi-voltage electrical system (5V, 12V, 120V relay control) to support sensors, actuators, and control hardware

• Built and tested actuation mechanisms, including a water delivery system and servo-driven spray system

• Designed physical housing and system layout, including enclosure constraints and component organization

Technical Details

• Implemented a three-stage response sequence triggered by simultaneous motion and sound detection, improving reliability over single-sensor systems

• Utilized MOSFETs and relays to safely control higher-power devices from a microcontroller

• Designed actuator system using a high-torque servo (25 kg·cm) to mechanically trigger a spray mechanism

• Integrated a water pump system for fluid-based actuation and tested flow performance under control conditions

• Developed wiring architecture with shared grounding and distributed power supplies to ensure stable operation across subsystems

Results / Impact

• Successfully demonstrated reliable dual-sensor detection, reducing false positives compared to single-sensor triggering

• Achieved sequential actuation of multiple subsystems, validating control logic and system timing

• Demonstrated effective integration of mechanical actuation with electronic control systems

• Identified key design improvements, including enclosure sizing, wiring organization, and potential PCB integration for scalability

• Built a functional proof-of-concept for low-cost, modular security systems

Tools & Skills

Electromechanical Systems, Arduino Integration, Sensor Integration, Power Electronics, Prototyping, System Integration, Mechanical Design