The LPS001WP from STMicroelectronics is a tiny silicon pressure sensor that provides high resolution measurements of pressure and altitude in a compact and thin package which is suitable for use in smartphones, sports watches, and other portable equipment, as well as in weather stations and automotive and industrial applications. It can be used to enhance portable devices with GPS functions to identify its precise location in all three dimensions; i.e. not only the location of the building but also the particular floor. The sensor has an operating pressure range of 300 to 1100mbar, corresponding to the atmospheric pressures between -750 and +9000m relative to sea level, and can detect pressure changes as small as 0.065mbar, corresponding to 80cm of altitude. It is manufactured using a proprietary technology called VENSENS that allows the pressure sensor to be fabricated on a monolithic silicon chip, eliminating wafer-to-wafer bonding and maximising reliability. The pressure sensor is based on a flexible silicon membrane above an air cavity with a controlled gap and defined pressure. The membrane includes a piezoresistor which reacts to changes in external pressure. The change is converted to a digital value that can be read by the host processor using the I2C or SPI communications protocols.
