Inspiration

Pedestrian crossings are one of the most dangerous places in a city: pedestrians, cyclists and cars share the same space, and many accidents happen simply because someone notices the others *too late. We asked ourselves: what if the crossing itself could see what's coming and warn people *before a conflict happens?

That's how BeSafe was born.

What it does

BeSafe turns an ordinary crossing into a smart one. Using a camera and an Arduino UNO Q, it:

  • detects pedestrians, cyclists and vehicles in real time
  • estimates speed and trajectories to predict a possible conflict before it happens
  • triggers light and sound alerts when the situation becomes dangerous
  • counts crossings by direction, producing useful data for the city

All the AI runs locally on the board: no cloud and no video leaving the device, which is better for privacy and latency.

How we built it

  • Arduino UNO Q: the Linux side runs the Python computer-vision pipeline, while the microcontroller drives LEDs, buzzer and display.
  • Arduino App Lab: used to develop, connect and deploy both parts of the app.
  • Danger rule: for each detected object we estimate its velocity $v$ and its distance $d$ from the crossing area, and compute the time needed to reach it:

$$ t = \frac{d}{v} $$

If a vehicle's $t$ falls below a threshold $\tau$ while a pedestrian is crossing, the system raises an alert.

  • Real-time web dashboard (HTML, CSS, JavaScript, Socket.IO): it shows the live video with detections, the current danger state, adjustable thresholds and crossing counters.

We tested BeSafe on a real crossing in Turin.

Challenges we ran into

  • Running AI on the edge: getting detection fast enough on a small board meant balancing accuracy and speed.
  • From positions to predictions: turning noisy frame-by-frame detections into stable speed estimates was harder than expected.
  • Two worlds on one board: making the Python side and the microcontroller talk reliably in real time.
  • The real world: changing light, occlusions and unpredictable people behave very differently from a test video.

What we learned

  • How to build an end-to-end edge-AI system, from sensors to alerts.
  • How to design a simple but effective risk rule and tune its thresholds on real data.
  • How to work fast as a team under hackathon pressure, splitting hardware, AI and interface work.

What's next

  • Better trajectory prediction with tracking models
  • Smarter thresholds that adapt to traffic and time of day
  • A pilot installation on more crossings to collect long-term data

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