Example implementations are directed to a system that can be used to monitor the state of an occupant of a structure, such as a bed or a mattress. The states that can be monitored include whether or not the occupant is present, the position of the occupant, entry or exit of the occupant, and other signs that can be detected via movement, such as activity level, breathing, epileptic seizures, and heart rate. Example implementations involve one or more accelerometers disposed on the structure, such that the movement or changes in position by the occupant is transferred to the accelerometers, and a computing system to process the data from the accelerometers.