It is important that the south pole of the magnet be facing towards the Hall effect switch. If the magnet’s polarity is reversed, the switch will not function. The south pole is marked at with a black dot.
The neodymium disc magnet produces a strong magnet field. Do not place it near sensitive electronic (i.e., computers with hard drives). The magnet should be stored in the packing foam and kept at a distance from any electronic items in the lab or storage area.