How to measure a magnetic field

[pdm]

Hi,

I hope that's the correct forum. So I'd like to play around with electronics and magnetism. Meaning: I'd like to build myself a electro magnet and then do some fancy stuff with it. Probably I'll try to recreate this https://www.reddit.com/r/woahdude/comments/881wgw/ferrofluid_inside_of_a_rotating_magnetic_field/

Question 1:
Assume I have a magnet, like your refrigerator magnet or whatever. I'd like to measure its magnetic field. How would I do that? What equipment would I need and how would I actually measure it? I guess I'd use some equipment to obtain data points in 3D space, right and then just interpolate it, right? How to protect from noise easily?

I'd like to build the equipment myself, so just buy the acutal sensors but without all the other stuff. (Mainly to get into electronics again a bit)

Question 2:
If I buy a magnet, there'll probably be a facts sheet about all that right? If so, is there a good shop where I can buy magnets? I'd prefere a shop that is environmental and fair trade etc. etc.

Thanks :)

 

[DaveE]

Probably the best DIY method would be based on commercially available hall effect sensor ICs. Look at Melexis MLX91209 for example. You would need to provide some simple circuitry to power it and measure it's output.

 

[jim hardy]

A search on "hobbyist DIY gaussmeter" will find how-to=build-one-articles.
one of many
https://www.kjmagnetics.com/blog.asp?p=gaussmeter

 

[pdm]

thanks :) That's a start.

 

[jim hardy]

I bought a copy of this book while its late author was alive.
It is the best treatment i have ever seen.
If you find a copy grab it.

https://www.amazon.com/dp/B0006QVDJK/?tag=pfamazon01-20

I really hope somebody buys the rights and re-issues it. Ahem - Dover Press are you listening ?

 

[donpacino]

One thing you will need to remember. The Earth (and other structures, items, electronics, anything really) will generate a magnetic field. This will NOT be uniform and could change based on time and your location. Your reading will also change based on the angle and direction of the gaussemeter probe (read about magnetic field lines).

What is the takeway. Zero your probe before use in the orientation you plan on using it at the location you plan on using it. If you are going to try readings at different angles, distances, etc, you may want to get a baseline to know how your environment will affect your probe readings.

I hope I am not overcomplicating this for you

 

[pdm]

I bought a copy of this book while its late author was alive.
It is the best treatment i have ever seen.
If you find a copy grab it.

https://www.amazon.com/dp/B0006QVDJK/?tag=pfamazon01-20

I really hope somebody buys the rights and re-issues it. Ahem - Dover Press are you listening ?

going to take a look, thanks!

One thing you will need to remember. The Earth (and other structures, items, electronics, anything really) will generate a magnetic field. This will NOT be uniform and could change based on time and your location. Your reading will also change based on the angle and direction of the gaussemeter probe (read about magnetic field lines).

What is the takeway. Zero your probe before use in the orientation you plan on using it at the location you plan on using it. If you are going to try readings at different angles, distances, etc, you may want to get a baseline to know how your environment will affect your probe readings.

I hope I am not overcomplicating this for you

I don't really get what you mean with baseline but it's not the first data-colelction/experimentation I'm doing, so I'm aware that there are lot's of noise-sources and such. One though I had was to buy magnet where I have a data sheet so I can check how well my gauss meter actually works (if there are such magnets with such data sheets) - could also be a nice way to check for any noise sources. Anyway, I'll just start building it and see what happens then.