Differential piezoresistive wind speed sensor on flexible substrate

In this Letter, a differential piezoresitive wind speed sensor on a flexible substrate is proposed. Two piezoresistors with the same size are fabricated on the front surface and back surface of the substrate, respectively. When the wind blows towards the device, the flexible substrate is bent, increasing the resistance on the front surface and reducing that on the back surface. The proposed sensor is fabricated on a polyethylene terephthalate substrate. Wind speed experiments are performed in the wind tunnel and the results demonstrate that the sensor can measure the wind speed up to about 20 m/s.