We present a wrist worn fall detector for elderly people. The detector is easy to wear and offers the full functionality of a small transportable wireless alarm system. It implements a fall detection algorithm which will alert a call center after a heavy fall. This occurs even if the wearer is unconscious or too agitated to press the alarm button himself. The algorithm is designed to work with the fall detector attached to the wrist. This is probably the most difficult place for detecting a fall. The algorithm can therefore be expected to function at other locations on the body. The system combines complex data analysis and wireless communication capabilities in a truly wearable watch-like form. This paper summarizes the functionality, architecture and implementation of the system.