Doorbell

invention · home technology · sound signals

From cord to button. The very first doorbells were mechanical devices that you had to pull a cord to ring a bell inside. Today's doorbells use electricity and a simple pushbutton, making them much easier to use.

Electric power. Modern doorbells run on electricity, which makes the bell ring automatically when you press the button. This is much faster and more reliable than the old pull-cord system.

Security upgrade. Many new doorbells have tiny video cameras built in so homeowners can see who's at the door without opening it. Some even have intercoms so you can talk to visitors before they come inside.

Alert inside. When you press a doorbell button, it sends a signal that makes a bell or chime ring somewhere inside the building. This alerts the people inside that someone is waiting at the door.