Pressure plates are flat devices that respond to weight or force applied to their surface. They are commonly used in various applications, such as in security systems to trigger alarms when someone steps on them or in video games to activate mechanisms when a character stands on them. These plates can be made from different materials, including metal or plastic, and come in various sizes. When pressure is applied, they can send a signal to a connected system, allowing for automated responses or actions, making them useful in both industrial and consumer settings.