US Patent 10137802 Detecting occupant presence on a vehicle seat

A system for detecting that an occupant is present in a vehicle seat. The system includes a bladder disposed in the vehicle seat, a pressure sensor, and a fluid pump. A conduit provides a single line into the bladder, a first branch of the single line connected to the fluid pump, and a second branch connected to the pressure sensor. The pressure sensor is communicatively coupled to a computing device. The computing device is programmed to detect that the occupant is present in the vehicle seat according to two or more data, including a first pressure value and a second pressure value that is detected at a time following detection of the first pressure value.