Paper-based piezoresistive MEMS force sensors

This paper describes the development of piezoresistive MEMS force sensors constructed using paper as the structural material. The sensing principle of the paper-based sensor is based on the piezoresistive effect of conductive materials patterned on a paper substrate. The device is inexpensive (~$0.04/device for materials), simple to fabricate, lightweight, and disposable. The entire fabrication process can be completed within one hour in common laboratories with simple tools (e.g., a paper cutter and a painting knife), without requiring cleanroom facilities. The paper substrate allows easy integration of electrical signal processing circuits onto the paper-based MEMS devices. We demonstrated that the paper-based sensor can measure forces with moderate performance (i.e., detection limit: 120 μN, measurement range: ±16 mN, and sensitivity: 0.84 mV/mN), and applied the sensor to characterizing mechanical properties of soft materials. We also developed a paper-based weighting balance with a measurement range of 15 g and a resolution of 25 mg.