Hot water scalding Edit
Insert temperature sensor in the showerpipe to automatically shutoff all water if it rises above a certain temperature.
Combine the hot and cold water pipe of the bathtub into one pipe for the temperature sensor to measure.
Every year there are people with health problems fainting in their shower and getting burns in their unconscious state. Thousands of children gets hotwater burns from the bathtub, a simple temperature measureing circuit will prevent these domestic accidents.