Sensirion AG, Staefa, Switzerland, offers noninvasive liquid flow sensors based on planar microfluidic substrates. The company's thermal flow sensor microchips measure noninvasively through the wall of a flow channel inside a microfluidic substrate, enabling sensitive liquid flow measurement and bubble detection in the microliter range. A small digital CMOSens microchip is bonded to the microfluidic channel substrate and houses the sensor element, digital intelligence, and memory for signal linearization, temperature compensation, and self-test algorithms. The chip provides an I2C interface and can operate over a 2.8–3.3 V supply voltage. Sensing response time is ~30 ms and sensor resolutions are down to 0.5 nl/min. Customized OEM solutions can be developed for high-volume applications.