Towards Encoder-Like Tactile Sensing via Conductive Beam Buckling

Commercial force sensitive resistors have multiple sensitivity and dynamic properties that limit their applications within tactile sensing. We introduce a piezoresistive force sensor that uses the buckling of a conductive serpentine to detect force. Contact between beam and the conductive sub-strate shunts current from the serpentine into the substrate to produce a discrete, “encoder-like” response to force. This mechanism makes the sensor response tunable through one process step and reduces the zero-load resistance to a value that can be measured by an analog-to-digital converter. We model and characterize sensor response, ultimately achieving a force sensitive range of 1.75 – 6 N.