The MS5701 from Servoflo Corp., Lexington, MA, is a MEMS low-pressure sensor with an I²C or SPI digital interface. Available in either differential or gauge models, the sensor can measure pressures as low as ±2.5 in.H₂O up to ±10 in.H₂O in a differential version. The gauge model has ranges from 2 in.H₂O to 20 in.H₂O. Supply voltage is 1.8–3.6 V, power consumption is 1 µA, resolution is 0.001 mbar, and conversion is 0.54 ms. A 24-bit pressure and temperature output allows for integration to a microcontroller and the I²C or SPI interface communicates up to 20 MHz. Typical uses include HVAC, respirators, ventilators, CPAP and sleep apnea devices, leak detection, and liquid level metering.