Single and double touch mode capacitive pressure/force sensing technique and approach*

The cantilevers and diaphragms are extensively explored mechanical elements to design and fabricate normal mode capacitive pressure sensors. However, monitoring large pressure ranges and obtaining linearized capacitance change response w.r.t pressure is quite challenging. Therefore, in order to investigate and solve the problem, single-touch and double-touch mode capacitive sensing techniques are explored. The affordable materials such as aluminium-coated polyimide foil, double sided tape, polyimide tape and posted paper are utilised to fabricate the sensors. The experimental characterisation of sensors is performed using developed air-pressure set-up which is experimentally calibrated using commercially available (MS5803-14BA) micro-pressure sensors. The CO₂ Laser (Universal Laser Systems PLS6.75) is utilised to cut the diaphragms, double-sided and polyimide tape. The Keithley Semiconductor Characterization System (Model-4200 SCS) is used to perform capacitance measurements for characterizing the sensor. The fabricated single-touch mode capacitive pressure sensor shows linear response for 10-40 kPa pressure range, whereas double-touch mode capacitive pressure sensor shows linear response of 14.24-54.9 kPa.

Ref:

1. R B Mishra, S M Khan, S F Shaikh et al. (May, 2020) in 3rd IEEE Int’l. Conf. on Soft Robotics (RoboSoft), pp. 194-200.
   
   R B Mishra, W Babatain, N. El-Atab et al. (Sept, 2020) in 15^th IEEE Int’l. Conf. on Nano/Micro Engineered and Molecular System (NEMS), pp. 95-99.