I have to detect a magnet with an Arduino for a personal project. I was wondering if using a magnetoresistor and detecting the current drop was possible. I understand that using a Hall effect sensor is the easiest method, but I wanted to know if it was possible. How would I integrate it in this case.

  • \$\begingroup\$ Where are you going to get a magnetoresistor from? \$\endgroup\$
    – DKNguyen
    Apr 8, 2020 at 3:21
  • \$\begingroup\$ Unclear at present, I was just wondering if it was possible, and not considering the specifics of sourcing \$\endgroup\$ Apr 8, 2020 at 3:33
  • \$\begingroup\$ Then yes, lots of things are possible. Is it possible questions tend to be bad questions to ask since they are extremely broad, close-ended questions and no one really learns anything from the answers. \$\endgroup\$
    – DKNguyen
    Apr 8, 2020 at 3:35
  • \$\begingroup\$ How would I integrate it in that case\ \$\endgroup\$ Apr 8, 2020 at 3:36
  • \$\begingroup\$ Well, first you need to get a magneto resistor and I guess wrap a bunch of wire around it like an inductor to concentrate the magnetic field so the effect is increased for the same amount of current? But good look finding a magneto resistor on its own. \$\endgroup\$
    – DKNguyen
    Apr 8, 2020 at 3:38

1 Answer 1


To detect a magnet it is useful to start by using a magnetic field detector. "detecting the current drop" is a step off the main path - unless you are actually trying to detect a current drop - if so, you should say so.

A Hall sensor does just what you want - and is available off the shelf at good

prices and with well defined characteristics - why would you not start there?

A GMR (giant magneto resistive effect) sensor measures change in magnetic alignment - also off the shelf. (vaguely closer to what you want)

A MEMS gyroscope and accelerometer package often incorporates a 3 axis magnetic field detector as a bonus, What's not to like?

A fluxgate sensor will probably do what you want.

Even a mechanical deflecting sensor (compass needle like) can be bought or built from scratch.

All have the advantage of availability and or working in a known way.

But and :-) - you can but magneto resistive sensors off the shelf - eg here - from Arrow


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