Development of Low Cost, Fast, and Highly Stable Piezoresistive Strain Sensors to Monitor Human Movement

A low-cost, easy-to-fabricate, and highly sensitive piezoresistive strain sensor was designed in this study. A well-known conductive polymer, for example, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), was deposited on the latex-free elastic bands to prepare the strain sensor. The sensitivity of the proposed sensor was about 4.27 over the wide strain measurement range of about 0%–83%. The sensor also exhibited a good hysteresis response; highly stable sensing performance with a relative standard deviation (RSD) value of about 1.32%; good linearity, that is, the correlation coefficient,
${R}^{{2}}$
, value of about 0.987; and high reproducibility. The proposed strain sensor was installed on different joints of the human body to observe the movement of the human body, and satisfactory results were obtained. In addition, the proposed strain sensing element provided a fast response and recovery time of about 1.74 and 3.73 ms, respectively. Index Terms— Conductive polymer, linearity, piezoresistive, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), stability, strain sensor.