A CMOS strain sensor has been fabricated in a 1μm FD SOI CMOS process. It is based on the piezoresistive effects of PMOS transistors and integrates a frequency conversion circuit. Testing of the chip mounted on a bent hard steel blade shows fair sensitivity for 10 μW power consumption.
Rue, B., Olbrechts, B., Raskin, J.-P., & Flandre, D. (2011). A SOI CMOS smart strain sensor. Proceedings of the IEEE International SOI Conference (SOI 2011), 1-2. https://doi.org/10.1109/SOI.2011.6081791