Google recently filed a patent specification relates to systems and methods for controlling a hazard detection system. More particularly, this patent specification relates to systems and methods for managing alarming states and pre-alarming states of the hazard detection system.

Hazard detection systems, such as smoke detectors, carbon monoxide detectors, combination smoke and carbon monoxide detectors, as well as systems for detecting other conditions have been used in residential, commercial, and industrial settings for safety and security considerations. Many hazard detection systems operate according to a set of standards defined by a governing body or companies approved to perform safety testing Conventional hazard detection systems that operate solely based on these thresholds might be characterized as being relatively limited or simplistic in their modes of operation. For example, their mode of operation may be binary: either sound the alarm or do not sound the alarm, and the decision whether to sound the alarm may be based on a reading from only one type of sensor. These relatively simple and conventional systems can bring about one or more disadvantage.

Patent no.-US9, 704,380 “Methods for using state machines”

Systems and methods for using multi-criteria state machines to manage alarming states and pre-alarming states of a hazard detection system are described herein. The multi-criteria state machines can include one or more sensor state machines that can control the alarming states and one or more system state machines that can control the pre-alarming states. Each state machine can transition among any one of its states based on sensor data values, hush events, and transition conditions. The transition conditions can define how a state machine transitions from one state to another. The hazard detection system can use a dual processor arrangement to execute the multi-criteria state machines according to various embodiments. The dual processor arrangement can enable the hazard detection system to manage the alarming and pre-alarming states in a manner that promotes minimal power usage while simultaneously promoting reliability in hazard detection and alarming functionality.