AquaSafe

System

Architecture

The system consists of three main components: A poolside computer, A Cloud Server and An iOS app

Technical Components

Main Unit:

Battery powered raspberry pie with a webcam, microphone, temperature sensor and two wifi dongle. The unit will monitor water temperature and alert whenever someone goes into the pool as identified by the webcam. The device will be located outside the pool in a waterproof case.

Cloud:

The Cloud Server collects all readings and alerts into a DB which will also serve as an endpoint for the mobile app (REST and Push notifications).

Mobile:

The iOS mobile app allows the user to view information about water quality, a history of alerts including an image of the alert. Most importantly, the iOS app will serve notifications whenever someone goes into the pool.

Algorithms:

In order to detect when someone is in the pool (activity detection) we are using OpenCV to compute the difference between frames in a sliding window approach. Each frame is first converted to gray scale and then slightly blurred. We then accumulate the weighted average of the current frame and the previous frames in the window. We then compute the difference between the current frame and the running average. Once we obtained the delta frame we threshold and dilate it to fill any holes. Finally we're using openCV find contours method to search for objects in the frame. The sliding window approach allows us to ignore object that are either constant or moving very slowly (such as a pool robotic cleaner).

Prototype

Screenshots from the AquaSafe iOS App: