This paper describes the work carried out to implement a wireless sensor network capable of automatically evacuating a building. A distributed computing cloud was created in nesC for TinyOS and two different types of evacuee detection sensors were designed and tested. LED display boards were designed from first principles and used to guide evacuees to the nearest exit. Control room software was developed to display evacuation data to a control room operator and used a building overlay together with graphs and charts to display the information in several meaningful ways. The system was successfully deployed at the Council of Scientific and Industrial Research (CSIR) and several tests were conducted. The distributed computing cloud functioned as expected, directing evacuees along the most effective routes, based on routing metrics acquired during the evacuation. The system was able to re-route evacuees based on congestion estimates, additional evacuation triggers and manual overrides.