Design And Implemention Of A New Solid State Wind Speed Sensor

The measurement of wind speed plays a vital role in people's life.There are various anemometer made of different measurement methods,including the wind cup anemometer,ultrasonic anemometer and thermal anemometer.With the continuous development of modern technology,the sensor preparation technology is more and more mature,but the existing anemometer in the wind speed measurement have defects.In addition,the requirements of low power consumption and high reliability of sensors are increasingly urgent.Piezoresistive anemometer is widely concerned because of its good mechanical and electrical properties.A anemometer based on piezoresistive detection is proposed,which can measure wind speed and direction simultaneously,the sensor measurement is not affected by the environment,and has the characteristics of low power consumption and stable structure.The sensor designed in this paper uses the thin-walled spherical shell as the wind sensing component to convert wind speed information into wind pressure,and the wind pressure is transferred to the bottom of the elastomer through the mechanical conduction of the central copper column.The cross cantilever beam in the elastomer is deformed under the action of tangential stress and normal torque and produces strain on the cantilever beam.The wind speed and direction can be calculated according to the strain on two vertical cantilever beams.At first,the structure of the sensor is designed.The CFD module in COMSOL software is used to simulate the flow model around a spherical sphere,and the stress of the cross cantilever beam under different static loads is analyzed by using the solid mechanics interface.The relationship between the sensor strain and the structure size of the center cylinder and the cantilever beam is established,and the reasonable structure size is selected,and the processing and assembly of the sensor are completed.Secondly,the design of the sensor hardware circuit and the development of the software are carried out to determine the sticking position and connection mode of the strain gage on the cross cantilever beam.The strain gage constitutes Wheatstone full bridge circuit and outputs the differential signal.The weak signal amplification circuit is designed to amplify the differential signal output by Wheatstone bridge,and then the amplified analog signal is converted into digital signal.The microcontroller communicates with the ADC through the I2 C protocol.The MCU uses the serial port to transmit data with the PC terminal to get the information of wind speed and direction.Finally,the sensor sample was tested.The measurement range of the sensor wind speed was 0?25m/s,the measurement error was less than ±(0.4m/s+0.05v),the measurement range of the wind direction was 0?359°,the measurement error was less than ±7.8°,and the average power consumption was 209mW.