I have an application, where I want to detect proximity of conductive materials (including humans). The idea is that I have a series of conductive sense strips and I measure capacitance between each pair consecutively.
I found an AD7147 CDC datasheet and tested it out in differential mode, seems to work just fine. What troubles me is distance between the sense strip and the IC, which can reach 2m. Obviously cabling should be shielded, IC even provides separate shielding ground pad. Since I'm not interested in absolute value but only dynamic change in measurement, any coaxial cable with fixed capacitance-per-length should do, right? As long as length remains fixed and cable itself is fixed to avoid triboelectric effects.
Are my assumptions correct or am I missing anything? Are there any known issues (possibly from analog accelerometer world) with such a setup?