The software is based on OpenCV, more specifically the opencv library for Processing. OpenCV contains all sorts of tools for image processing, one of these being face tracking. The image of the webcam is being searched for a face. The height and the size (~distance) of the detected face is compared to a set threshold. If the thresholds are exceeded for more than two seconds the alarm will sound and then silence after a few seconds. If the user gets up from his chair or the face is not visible the alarm will not be triggered. The alarm itself is just the Windows error sound. The user interface consists of the live image in the background. Three buttons are for setting up the limit values and for pausing the alarm.