A 50mW CMOS wind sensor with ±4% speed and ±2° direction error

This paper describes a smart CMOS wind sensor that measures wind speed and direction without moving parts. It combines a 2D thermal flow sensor and the required readout circuitry on a standard CMOS chip. The flow-dependent heat distribution in the chip is controlled and digitized by two thermal delta-sigma (TΔΣ) modulators. Both wind speed and direction can then be determined from their bitstream outputs. For wind speeds ranging from 1 to 25m/s, the sensor´s error is less than ±4% (speed) and ±2° (direction), while consuming 9χ less power than a previous design.