A Resistance Change Detection Circuitry for Thread Based Resistive Sensors

Resistive pressure sensors such as strain gauge’s have immense industrial applications due to low-cost and moderate to high sensitivity. Their applications have grown recently with the advancement in flexible resistive pressure sensors. However, the resistance of these sensors is highly affected by drift and offset resistance. Conventionally, voltage dividers and Wheatstone bridge-based circuits have been used for interfacing such sensors. However such interfacing circuits need calibration for offset resistance compensation. But the problem due to drift in resistance is still present. In this paper, a novel circuit is proposed to compensate for the offset and drift of these sensors. The proposed circuit detects the change in resistance using auto-zeroing feedback loop. The proposed circuit is tested with a fabricated thread-based pressure sensor for touch detection. Experimental results show that R variations as low as 10 $\Omega$ can be detected with a wide range of sensor resistance measurement. The error of measurement in sensor resistance is less than 1%.