That would still make it a two wire sensor but what do I know. On the other hand, if this is a Hall effect sensor as you say, where does the resistance come from? I know an inductive sensor is a wire wrapped around a permanent magnet and will have resistance on it, but not sure where resistance comes from in a Hall effect. As well, a Hall effect sensor has to have power, ground and signal so how do these two wires pull that off? I have a Picoscope and generally, all 3 wire sensors that are digital, emit a nice square wave pattern. I don' t see that in your pattern?