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Detecting a small magnetic field using Hall Effect Sensor
I have a problem, i want to detect a magnet which have a small magnet for a long distance using Hall Effect Sensor.
By Anonymous on 7 June, 2003 - 2:21 am

I have a problem, i want to detect a magnet which have a small magnet for a long distance using Hall Effect Sensor. I want more information for that.

Several types of Hall Effect Sensors are on the market today with unlimited connections (+, -, ground) use. Usually they are N/O (normally open) and close on detection of a magnetic field. Some models are single pole meaning the magnet needs to be in the correct direction for detection and some models are bipolar. Power is low voltage controlling a transistor plus you usually need an amplification circuit You can email from the link below with a request for some ideas on small circuits for you to look at. We have nothing on line to link to.

I would highly recommend a simple reed switch. They are cost effective, very dependable work in most any direction and are either off or on. Amplification circuits are not required as it is either off or on. Check out what a reed switch will control at:

Bob Hogg

By Vlad Feldman on 10 June, 2003 - 5:35 pm


check-out ALLEGRO, INC web site

Thx Vlad

By J. Baxter on 18 July, 2003 - 3:17 pm have a good selection of hall sensors in a variety of industrial packages. They are unipolar, bipolar, switched, analog latch with different o/p's and operating voltages. connectorized or flying leads.

By Rob Beers on 9 August, 2003 - 6:13 pm

Did you find the solution? I was also looking to make an oak chessboard with magnetic sensors under the board to sense the position of the peices. The chess peices would have a small magnet in them. It would be nice if a reed switch would work. I will have to get some and try. If you find an answer please let me know too. Thank You very much.


I am making a similar sensor to detect 1 meter using a LVDT with a long shaped core and a small magnet. You can contact me for more details.
good luck!

I am looking for a sensor to detect a 4mm neodymium magnet from a distance of 5cm.

With a small magnet. I can communicate.

Can anyone help me with more details?