Anybody working with magnetic field sensors? We want to measure ambient (ballpark 1 gauss) single-axis field strengths in a room, probably at several locations. We need a DC coupled field strength transducer. We're mainly interested in changes, so a little zero offset would be OK, but we need pretty good stability in a lab environment, like maybe 0.02 gauss drift in 24 hours. Bandwidth a few hundred Hz maybe.
There are fluxgate sensors for this, OEM boards in the range of $40 to $400 roughly, but I was wondering if there might be any chip-type Hall or GMR sensors that have this sort of sensitivity.