We are working on a project to measure the angle of a metal flap inside the plastic tube where copper coil is winded outside the pipe and at first we were working with 900 turns,36 gauge copper coil where the drift was almost negligible but when started to work with 50 turns, 22 gauge copper coil the inductance value is drifting like sinusoidal(decreasing and increasing randomly). we are using only channel 0 and metal we used as a flap is stainless steel. please help me regarding the problem and with possible solution.