US Patent 7617734 Pressure sensor with dual chamber cover

A pressure sensor assembly is provided for fitting within the valve stem of a vehicle tire. The assembly comprises a substrate assembly defining a plurality of holes. A pressure sensor and a temperature compensation sensor are mounted to the substrate assembly. Each sensor includes a deflectable membrane defining a first chamber and a cap mounted to the membrane to form a second chamber. A cover is provided for engaging with the pressure sensor and the temperature compensation sensor to define an active chamber and reference chamber respectively. The active chamber is exposed to tire pressure when the pressure sensor assembly is fitted within the valve stem whereas the reference chamber is sealed from tire pressure.