5Pcs Hall Effect KY-003 Magnetic Sensor Module DC 5V For Arduino PIC AVR Smart Cars

Have used these to make a tachometer for my lathe. Using rare earth magnet these are working with over 5mms clearance. Note they are unipolar - only sense one magnetic pole not both.

Not linier

Excellent value for money getting 5, used in a fairly high precision application and took quite a lot of tuning to get them to respond well, but would work perfectly if all you need is a rough proximity sensor or similar.

I wanted these to work with Arduino to detect a passing magnetic field. Unfortunately, they were not sensitive enough.

even in the simplest setup, all 5 seem to be made to latch - they return low when exposed to one pole, then remain so until exposed to the opposite pole.

These work as advertised, but the sensitivity is quite low and can't be adjusted. With the magnets I'm using, they had to be in contact with the sensor before it would activate, I need it to work with a 5mm air gap and can't use a stronger magnet. I have hall effect devices of a different type, now out of stock which worked like this and assumed these would be similarly sensitive.

What I said above. Item works but not as expected! The item provided is a latching hall effect sensor ie: North turns ON, and it remains on (despite absence of magnet) and only turns OFF when South is detected. It has useful applications so I won't be returning but this is CRITICAL information to provide when selling these components / modules hence the 3 stars. Read distance is about an inch (through hand) with an N50 rated 10x2mm circular neodymium magnet which is excellent.