Project Type
Senior Capstone
Mechanical Engineering Senior Capstone
Emergency Alert
Recognition System
A compact automotive system that recognizes emergency sirens and vehicle horns and communicates them through visual alerts for deaf and hard-of-hearing drivers.
Functional Prototype
Final EARS prototype and visual-alert interface
Final Controller
ESP32
My Focus
Mechanical Design & Validation
Outcome
Functional Prototype
The Problem
Making Audible Warnings Visually Accessible
Emergency sirens and vehicle horns provide critical information to drivers, but those warnings may not be accessible to someone who cannot reliably hear them.
The project required a compact system capable of detecting target sounds, processing them quickly, and presenting a clear visual alert without distracting or obstructing the driver.
My Contribution
Mechanical Design and Validation
- ●Supported product requirements, concept development, and engineering documentation.
- ●Developed and refined compact electronics-enclosure concepts.
- ●Conducted thermal analysis of the ESP32 and enclosure.
- ●Supported 3D printing, assembly, drop testing, placement evaluation, and prototype validation.
Product-Development Process
From User Need to Tested Prototype
The project followed a complete engineering process rather than beginning directly with a final enclosure or circuit layout.
STAGE 01
Define the user need
Identify the difficulties deaf and hard-of-hearing drivers may experience when emergency sirens or vehicle horns are not visually apparent.
STAGE 02
Establish design requirements
Develop measurable requirements covering detection behavior, response time, visibility, size, cost, thermal conditions, installation, and durability.
STAGE 03
Evaluate system concepts
Compare microphone, processing, alert, power, enclosure, and mounting concepts before selecting the most practical complete system.
STAGE 04
Prototype and validate
Integrate the microphone, controller, visual indicators, enclosure, and software before conducting thermal, drop, mounting, and demonstration tests.
Embedded-System Architecture
Detect, Process, and Communicate
The final architecture connects audio sensing, embedded processing, visual communication, and protective mechanical packaging.
1
INMP441 Microphone
Captures environmental audio and provides a digital signal for emergency-sound classification.
2
ESP32 Controller
Processes the incoming audio signal and activates the appropriate visual alert when a target sound is detected.
3
LED Pictograms
Communicate detected sirens or horns through recognizable visual symbols positioned within the driver’s field of view.
4
ASA Enclosure
Protects the electronics while supporting automotive temperature resistance, ventilation, mounting, and manufacturability.
Environmental Audio→INMP441 Microphone→ESP32 Processing→Visual Alert
Concept Evolution
Comparing Processing Architectures
Arduino Concept
Early architecture used to evaluate basic electronics packaging and visual-alert placement.
Raspberry Pi Concept
A higher-processing-power alternative evaluated during system architecture development.
Final ESP32 Architecture
Compact final direction selected for embedded processing, packaging, and prototype integration.
Mechanical Design
Enclosure Development
The enclosure evolved as the internal electronics changed and requirements related to assembly, airflow, size, visibility, and manufacturability became clearer.
Primary Mechanical Challenge
Thermal Performance Inside a Parked Vehicle
Electronics inside a parked vehicle may experience temperatures far above normal room conditions. The enclosure therefore needed to be evaluated as part of the thermal system rather than merely treated as protective packaging.
Worst-Case Condition
Parked Vehicle
High-temperature cabin exposure
Predicted ESP32 Surface
≈ 88°C
Initial worst-case thermal result
Design Response
Ventilation
Airflow openings added to enclosure
Storage Guidance
Glove Compartment
Recommended when the vehicle is parked
Design Response
Ventilation openings were incorporated into the enclosure, and storage guidance was added to reduce prolonged thermal exposure when the vehicle is parked.
Prototype Validation
Mechanical, Thermal, and User Testing
Drop Resistance
PassedThe enclosure was evaluated through a three-foot drop scenario without permanent deformation affecting the intended function.
Thermal Performance
Design RevisedThermal analysis identified elevated internal temperatures, leading to ventilation features and safer placement recommendations.
Driver Visibility
Mounting EvaluatedSeveral mounting locations were compared, with placement above the steering wheel providing strong visibility and response potential.
Emergency-Sound Demonstration
FunctionalThe prototype demonstrated visual responses to ambulance, police, fire-truck, horn, and alternative sound inputs.
Functional Demonstration
Emergency-Sound Testing
The following demonstrations show the prototype responding to several emergency and roadway sound inputs.
Ambulance Siren
Prototype response when presented with an ambulance siren input.
Police and Fire-Truck Sirens
Visual-alert response to additional emergency-vehicle siren patterns.
Vehicle Horn
Demonstration of the horn-detection alert behavior.
Alternative Sound Input
Additional prototype test used to evaluate system response under another audio condition.
Project Outcome
A Complete Engineering Prototype
The project produced a functional physical prototype supported by product requirements, CAD development, embedded electronics, thermal analysis, testing, manufacturing documentation, and user instructions.
The result demonstrated the feasibility of converting emergency audio cues into visual information while identifying clear areas for future improvement in classification performance, environmental validation, and automotive integration.
Reflection
Lessons Learned
Requirements improve engineering decisions
Establishing measurable requirements made it easier to compare concepts and justify decisions related to size, cost, temperature, mounting, and usability.
Architecture should match the real product
The final controller needed enough processing capability for the application without introducing unnecessary size, power consumption, or packaging complexity.
Automotive environments create harsh thermal conditions
An enclosure that performs well indoors may experience significantly higher temperatures inside a parked vehicle and must be evaluated accordingly.
Mechanical design influences electronics reliability
Ventilation, component spacing, mounting, material selection, and access for assembly all affected the performance of the embedded system.
Usability is part of engineering performance
A technically functional alert is not sufficient unless it is visible, understandable, and positioned where the driver can respond quickly.
Documentation completes the product
The final report, manufacturing manual, and user manual provide the information required to reproduce, assemble, operate, and improve the design.
Technical Documentation
Reports and Manuals
Final Capstone Report
Complete engineering process, requirements, analysis, design, testing, and conclusions.
View Final ReportManufacturing Manual
Fabrication, assembly, component, and manufacturing information for the prototype.
View Manufacturing ManualUser Manual
Installation, operation, handling, and user-facing guidance for the EARS prototype.
View User ManualEngineering Files