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Subscriber John Schuch writes:

Threads on the MAKE forums often touch on hall effect sensors for measuring current, position, speed, etc. I just got this link in an email this morning and think it’s pretty cool. Gotta love free technical training.

This is a sponsored tutorial on Digikey, sponsored by Honeywell, and promoting Honeywell’s line of magnetic sensors, but there’s still good info here. And the narrator sounds vaguely like Fox Sports announcer Joe Buck, if Joe Buck were a deep geek.

Magnetic Sensors

Gareth Branwyn

Gareth Branwyn is a freelancer writer and the former Editorial Director of Maker Media. He is the author or editor of a dozen books on technology, DIY, and geek culture, including the first book about the web (Mosaic Quick Tour) and the Absolute Beginner’s Guide to Building Robots. He is currently working on a best-of collection of his writing, called Borg Like Me.



  1. Sean says:

    Thanks for the heads up, just caused me to modify an order I was making to get the sensor I needed. That was timely!

    So, the circuit now includes one unipolar for switching and one analog to sense the level of magnetic field.

  2. Mike Miller says:

    John Schuch’s link to Honeywell’s magnetic sensor introduction prompted me to take a closer look at the digikey site. Turns out that they have a large series of useful “Product Training Modules” at , including one on Honeywell humidity sensors – just what I’ve been thinking I need to look for. Thanks for the tip!


  3. Mike says:

    I can find very little further information about circuits involving magnetoresistors online.

    What kind of range can you possibly get out of them? As in, how far away could you potentially sense, say, a rare earth magnet?

    Also, could one be wired to give a varying voltage rather than resistance?

  4. Mike says:

    I can’t find much information about Magnetoresistors online.

    What sort of range can you get with them? As in, how far away could one potentially sense say an average rare earth magnet?

    Also, could you get them to output a varying voltage rather than resistance?

  5. Jaclyn says:

    Can I make a magnetic sensor hook up to something and stop it from pulling something like a trigger?

    Can I make one from house hold items?

    How can I make one that has a range of 6-12 inches?

    And how can I make one with instructions that are simple?

  6. Jaclyn says:

    Hey the one that is up there ^ can you reply by march 10, 2010 |