Smoke detectors are one of the most important safety devices you can have in your home. They should be installed in the hallways and in the bedrooms. Smoke detectors provide early warning in the event of a fire, and enable emergency action in the event of a fire. They are inexpensive, easy to install, unobtrusive, and require very little maintenance, and no home should be without them.
Al smoke detectors consist of two basic parts: a sensor to sense the smoke and a very loud electronic horn to wake people up. Smoke detectors can run off of a 9-volt battery or 120-volt house current.