safechav:
They only produce an AC signal when the trigger teeth come and go. It doesn't really make a difference if you call the pins plus and minus or whatever, the point is that they must be wired the right way round.

xr3iturbo:
Waving is a bad word to descride what you should do. For instance, bring the sensor close to metal and stop it there. When you dont move it, you're not getting any voltage from it. Then rapidly pull the sensor away from the iron with a multimater connected and see if you get a brief positive or negative DC voltage reading. When you have it wired the right way round to the multimeter, it should give a negative reading when you take it further from metal (iron). If you just wave something in frot of the sensor you are just seeing bouncing +/- readings.