Abstract: Thermally-induced stress on a silicon micro-electromechanical pressure transducer (MEMS sensor) is reduced by attaching the MEMS sensor to a plastic filled with low CTE fillers that lowers the plastic's coefficient of thermal expansion (CTE) to be closer to that of silicon. The MEMS sensor is attached to the housing using an epoxy adhesive/silica filler mixture, which when cured has a CTE between about ten PPM/° C. and about thirty PPM/° C. in order to match the housing CTE. The adhesive also has a glass transition temperature (Tg) above the operating temperature range. This design provides good sealing of the sensor and stable sensor outputs.

Abstract: A vehicle telematics system repeatedly reports vehicle status, including the location of a stolen vehicle. As wireless reports are transmitted over time, battery capacity will decrease if the engine is not running. As the vehicle battery capacity decreases over time, status reports are adjusted to extend battery life and therefore the time over which at least some vehicle status information can be obtained.