**5. Conclusions**

This paper assesses the feasibility of a capacitance-based DEAP sensor technology for tactile pressure measurement in compression garmen<sup>t</sup> applications. The sensor is the outcome of a few generations of design iterations between the academic and industry partners. A series of tests were introduced to evaluate the e ffects of various factors on reliable in-situ pressure sensing. For the wide range of tests presented, the sensor has shown to have errors varying from ±1.8 mmHg for the bladder test to ±8.03 mmHg for the pneumatic sensor comparison test. The variation of the sensor sensitivity in response to mounting curvature was assessed. For sensors of smaller footprints, this becomes less significant. Temperature and humidity were studied and quantified for their impact on a bias error for the no-load capacitance value. The sensor calibration can easily help mitigate this as the sensitivity was shown not to be a ffected by these variables.

Compared to a pneumatic sensor, some of the advantages of the DEAP capacitive sensor design are its superior spatial resolution, manufacturability for smaller footprints, as well as its overall compact and simple design for use in array configurations measuring pressure distributions. This sensor performs at a high sampling rate of 285 Hz to allow measurements of abrupt pressure changes for physiological applications where a pressure pulsation may need to be tuned to a person's heartrate in order to increase cardiac output. The sensor is thin enough to be worn under a compression garmen<sup>t</sup> (thickness of 2.25mm). The durability shown during cyclic testing is attributed to the sensor being made of one solid component and no gaps within the sensor, as well as the compliance of the polymer solution used. Additionally, the perforated design will make the sensor more compliant to help prevent crack initiations during cyclic loading. Future sensor development can potentially improve performance, such as enhanced noise filtering using the electronics. As well, sensor geometry optimization should be further investigated using Finite Element Analysis to optimize the sensor's performance for the desired range of pressures. This includes investigating the trade-o ff between smaller sensor footprints, which achieves better spatial resolution and smaller curvature errors, but reduces the sensor's overall sensitivity.

**Author Contributions:** Conceptualization, S.L.; validation, S.L. and H.E.; investigation, S.L., H.E., and J.S.; writing–original draft preparation, S.L.; writing–review and editing, U.S., J.S. and A.S.; visualization, S.L., H.E., U.S., and J.S.; formal analysis, S.L., H.E., and U.S.; supervision, A.S.; funding acquisition, A.S.

**Funding:** This research was supported by a gran<sup>t</sup> from Lockheed Martin Corporation. The work was also partially supported by NSERC Canada through the discovery gran<sup>t</sup> program [NSERC DG 371472-2009].

**Acknowledgments:** The authors graciously acknowledge Chekema Prince and Iain Anderson and Sean Peterson for their valuable discussions, feedback, help with testing.

**Conflicts of Interest:** The authors declare no conflict of interest.
