Alarm sensors are critical to any alarm system as they provide feedback to the system about your home's security and status. Alarm sensors may be used to detect door and window opening, garage door opening, high or low temperature, humidity levels, smoke detection or carbon monoxide detection. Add water sensors to be notified in case of a water leak. Glass break detectors provide notification in case a window is attacked, damaged or breached. Photo beams are typically used to provide notification when someone walks through a passageway.