NightKnight


Inspiration

NightKnight is a portable, edge-AI powered safety device designed specifically for women and solo travelers staying in hotels, dorms, or short-term rentals.

We wanted to build a portable security system for women and solo travellers

By combining embedded systems and edge AI, we created a portable monitoring system that protects users in real time.


What It Does

NightKnight is an AI-powered smart door monitoring system that performs real-time image classification.

The system detects:

  • A person waiting in front of the door
  • A blackout or camera obstruction
  • Normal or unknown movement

If suspicious behavior is detected, the system triggers an alert response.

Key Features

  • Edge AI inference (no cloud required)
  • 96 × 96 image input model
  • INT8 quantized deployment
  • Real-time classification
  • Portable plug-and-play hardware

How We Built It

Hardware

  • Arduino Uno Q
  • Logitech Brio 100 HD webcam
  • USB-C interface

Software & AI Pipeline

  1. Collect labeled image data
  2. Train classification model in Edge Impulse
  3. Quantize to INT8
  4. Deploy model
  5. Integrate with hardware

Example class labels:

waiting_in_front
blackout
unknown


Model Summary

Component Description
Input Size 96 × 96
Quantization INT8
Classes 3
Inference Real-time

Challenges We Ran Into

  • Class imbalance causing incorrect predictions
  • Motion vs image classification confusion
  • Deployment troubleshooting
  • Real-time performance optimization

Accomplishments We’re Proud Of

  • [x] Trained and deployed a quantized edge AI model
  • [x] Achieved real-time inference
  • [x] Integrated camera + microcontroller + AI pipeline
  • [ ] Add infrared support
  • [ ] Develop mobile app integration

What We Learned

Through NightKnight, we learned:

  • Balanced datasets dramatically improve performance
  • Edge optimization reduces computation time
  • Hardware constraints influence model design

The prediction function can be expressed as:

( y = f(x; \theta) )

Where:

  • (x) = input image
  • (\theta) = learned weights
  • (y) = predicted class

Display version:

$$ y = \arg\max_i P(class_i \mid x) $$


What's Next for NightKnight

Future Improvements

  • Add infrared camera support
  • Integrate rechargeable lithium battery
  • Add video snapshot when triggered
  • Allow the application to actually call the emergency contact when the user selects that option
  • Train thermo-based classification model

NightKnight demonstrates how embedded hardware and AI can be combined to create practical, privacy-focused safety solutions.

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