Almost a year ago I had to make a small project for school in which to work with either images or sound or video (or altogether).

I chose to create something more interesting: a webcam alarm. It should work like this: if you’re away and something goes in front of the camera, then there is an intruder (unless it’s your cat ) and an alarm must be raised.

The main settings:

Frames ahead (or behind) – The number of frames that will pass before comparing the changes with the current frame. (for example comparing the 10th frame behind with the current frame). This is to detect if someone is moving extremely slow.
Sensitivity – How much must change before starting the alarm (ex: 0.05 – 5% - if more than sensitivity of the image has changed from the frames ahead then the alarm starts.
If the difference between the current frame and the frames ahead is above sensitivity then the alarm is started.

The attached solution has 2 projects: the client, which is the main application that uses the camera and starts the alarm and the server which the client informs about the intruder: it is just concept – my server just logs the info – but it can be extended to do more: notify the police, send the owner a SMS, etc.

Download WebCam Alarm.zip (621.69 kb)

I’ve been using code found on the internet many times. And usually the most important one was found on obscure sites/blogs where some people published it without much hope of being useful to many others. 

During time I wrote lots of code that I think some others might find useful but I didn’t bother to make it public.

So from now on, I’ll start to publish some of my code. Most of it will be found useful by few people, but as long as it makes one people happy, it worth my time to publish.