Development of water leakage detectors

Abstract: One of the highest costs in many apartments for insurance companies is due to water leakage. To prevent leakage from causing damage a detector can be placed in the sensitive areas to warn if a leakage should occur. This kind of installations does however lead to high installation costs, especially in already finished buildings, since they require a lot of wiring for communication. By using a wireless detector these costs could be lowered. In order for this to be achieved a sensor which is suitable to detect such water leakage has been connected to a wireless ZigBee transmitter which in turn is able to connect to a wireless network. The advantage with using ZigBee is that it provides much better range for less power compared to other solutions. The hardware includes a circuit that modulates the input from the sensor to have a more distinct behavior. The software part handles the communication with the ZigBee network and processing of the modified input from the sensor. To achieve a reasonable sensitivity of the sensor a circular buffer has been created to trigger on an average value instead of instantaneous. After reaching a satisfying design all parts were manufactured and tested to ensure that they work according to the design. In the course of the work some ways of improvements were found and implemented, resulting in a well working prototype.