STPMS1 Smart Sensor Device STMicroelectronics STPMS1 Smart Sensor Device is an ASSP designed to measure power line systems effectively utilizing the Rogowski coil, current transformer, or shunt principle. The STMicroelectronics STPMS1 Smart Sensor Device can be combined with an STPMC1 programmable poly-phase energy calculator IC as a building block for single-phase or poly-phase energy meters.