At Sensors Expo 2018, a product marketing engineer for ST Microelectronics demonstrates how a water-resistant pressure sensor mounted on a printed circuit board (PCB) can be submerged in water and provide accurate readings. With this capability, it has potential applications in wearable devices, altimeters and barometers for portable devices, GPS applications, weather station equipment, Industry 4.0 applications, utility meters, appliances and more.
The LPS33HW is an ultra-compact piezoresistive pressure sensor which functions as a digital output barometer having a 260 to 1260 hPa (3.77 to 18.27 psi) absolute pressure range and a 20x full scale overpressure capability. The 10-bar pressure sensor can withstand being submerged up to 90 meters. Its accuracy drifts by less than ±1mbar per year.
With embedded temperature compensation, the unit provides 24-bit pressure data output and 16-bit temperature data output in SPI and I²C formats. It has a current consumption as low as 3 μA with a supply voltage from 1.7 to 3.6 V. Available in a ceramic land gird array (LGA) package with a metal lid, the water-resistant pressure sensor is guaranteed to operate over a temperature range extending from -40°C to +85°C.
While most microelectromechanical systems (MEMS) pressure sensors come with user warnings regarding use in water and other liquids, with the advanced formula of its water-resistant gel filling, the water-resistant pressure sensor is resistant to chemicals like chlorine, bromine, and salt water, making it suitable for pool or sea measurement as well as resistant to soaps or detergents used when showering or cleaning.