# Visualizing Magnetic Fields In 3D Space

[John] is working on his PhD in experimental earthquake physics, and with that comes all the trials of becoming a PhD; tuning students into the cool stuff in the field, and demonstrating tech created after 1970 to his advisers. One of the biggest advancements in his line of work in the last 30 or 40 years is all those sensors you can find in your cell phone. The three-axis magnetometer in your phone is easily capable of measuring the Earth’s magnetic field, and this chip only costs a few dollars. To demonstrate this, [John] built a 3D compass to show off the capability of these sensors, and have a pretty light show for the undergrads.

The magnetometer [John] is using is just a simple I2C magnetometer that can be found on Adafruit or Sparkfun. It’s not really anything special, but with a little bit of code, [John] can read the magnetic field strength in the x, y, and z axes.

Having a microcontroller spit out a bunch of numbers related to the local magnetic field just doesn’t seem fun, so [John] picked up two neopixel rings – one inside the other, and set 90 degrees out of plane with each other. This turns his magnetometer and Arduino setup into a real 3D compass. With this device, the local magnetic field can be visualized in the x, y, and z axes. It looks cool, which is great for undergrads, and it’s a great demonstration of what you can do with small, cheap electronic sensors.

[John] put up a screencast of a talk he gave at the American Geophysical Union meeting last year. You can check that out below.

## 31 thoughts on “Visualizing Magnetic Fields In 3D Space”

1. Dave says:

Pretty sweet.

What are the boards in the video at 1:19? I am particularly interested in the topmost right one.

Uno, ??, ??, Intel Edison, BB Black, ??, ??, RPi

oops:

Uno, Paralax Propeller, ??, Intel Edison, BB Black, ??, MSP430, RPi

but I am still missing the two

1. Dave says:

I’ll take “Name that board” for \$500 Alex-
The board in the upper right corner is an NXP mbed LPC1768

2. Nickie says:

Missing ones are an Mbed and a Mojo v3

Thank you Brian (also Dave too). The video is really nice, thank you for posting it. Really really good!

3. untrustworthy says:

“… tuning students into the cool stuff in the field, and demonstrating created after 1970 to his advisers.”
“To demonstrate this, [John] built a 3D compass to show off the capability of these sensors, and have a pretty light show for the undergrads.”

Summary gore. HAD really needs an editor.

1. It’s impossible to edit something you have written, minutes after you’ve written it, with no errors slipping through.

It’s not an editing problem. It’s a resource allocation problem. I do not have the time or money to do what I want, to the quality I want. It’s like this with every single publisher, blog, news outlet, and website. I wash my hands of the problem and fix the errors as they’re reported in the comments. I don’t see anyone stepping up to fix the structural problems that allow these errors to exist, so shove it.

1. Alan Kilian says:

Thanks for all the ideas I’ve gotten from this site over the years.

I could care less about the errors.

:-)

1. untrustworthy says:

It’s: “couldn’t care less”

1. Nick says:

You can only use a colon at the end of a complete sentence.

2. bl says:

like brian says, its EVERY site these days. there is a push to get info out ‘fast, now!’ and so typos and such are a new fact of life. even old guard newspapers and magazines are filled with typos and grammar errors.

no one has money to pay proper editors or proofreaders, and that includes corporate work, too (I did some tech writing a long time ago and revisited it recently at a job I had and the difference from the text copy quality we had 20 yrs ago vs today is not even on the same ‘page’ (lol).

its sad that there simply is not money to pay proper proofreaders, writers and editors. its one thing for a hobby website but quite another when a cisco (etc) also could care less about their docs quality.

you either keep getting annoyed or just sigh and give up, writing it off to the new normal (ie, the race to the bottom for paying people what the job is worth rather than what you can get away with).

1. untrustworthy says:

It only takes a minute or two to re-read what one has written at least once or twice, however, with an eye toward proofing to english learned during highschool.

It’s like nobody even reads at least once the text they’ve written before posting. For a site that publishes articles, that’s an exceedingly low bar above which to hold them.

I don’t think it’s too much to ask that they take those couple minutes to check their work before publishing these articles and summaries.

1. Guess how I can tell you’ve never written anything for an audience bigger than a few people? You cannot edit something you have just written with 100% accuracy. It’s impossible, and ask anyone who writes and edits as part of their job. They’ll tell you the same thing.

With that out of the way, here’s why you’re an idiot: We judge the success of posts on a variety of factors, including views, social media shares, and the number of comments. If you complain, in a comment, about a spelling or grammar mistake, you are increasing the number of comments, and increasing the ‘success’ of a post. In fact, we’re getting more ad views from you; once when you first read the post, again after you comment (and the page refreshes), and again when you mash F5 a few times to see if anyone replied. By complaining about spelling and grammar mistakes, you are encouraging them.

I have told you I do not have the resources or the time to bring the quality of these posts up to where I want them. It’s not an editing problem, it’s a resource allocation problem. My only option now is to do the best I can. And here you come complaining, and actively encouraging these mistakes.

2. John doe says:

Well said Brian, show that ignorant readership!

3. For proof-reading you need another person in another mind state, if you just wrote something and then re-read it for proof-reading you will gloss over the errors you have just made, because you are in the haste to hit publish.

Like a math exam, you can look at your beautiful soup of greek alphabet and it all makes sense, until it is corrected by the professor, then when you receive it the error is in such plain sight that it hurts to see it there, written by yourself.

4. Tom says:

I have a solution that will make everybody happy: the grammar nazis, Brian, and the rest of us who are sick of arguments between the grammar nazis and Brian.

Drum roll…

Put the word “Draft” in the website template for each article.

5. tomás zerolo says:

No way to reply to Tom, but perhaps this lands on the right spot:

The “draft” idea is cute. Others call it “beta”…

A little enhancement:

(1) publish drafts under another URL, say /drafts/…

(2) leave them there for a (short) while, say 15 minutes.

(3) readers finding errors there can propose corrections, earning points towards a “prop”: 1500 points make a bus pirate or some such.

(4) after the time period expires, they’re out of draft. A merciless deadline scheduler.

(5) if someone complains about a speling eror in a published article, direct them to (1). Obviously those have the necessary skills and motivations — Win/win!

Announce the /drafts/ namespace prominently. Adjust parameters in (2) and (3) based on some geeky feedback algorithm.

3. j0z0r says:

You could get one of your loyal readers to do it *for free.* I’m also guilty of posting about it in the comments, although I have toned it down a notch or two after doing much more writing of my own. Now I only heckle about it if the error makes it significantly funnier, or completely breaks my understanding of what is being presented.

1. ^Much

FYI: Do be careful with your magnetic sensors as very strong magnets can damage the MEMS sensors. Read the datasheets/apps note for the sensor for that warning.

2. Mark says:

That’s not nearly as sensitive as a magnetometer.

3. eray says:

If you’re looking for a more permanent display, magnetic nail polish works surprisingly well:

4. I’ve had a sheet of this for years, only problem is pressure (mostly people letting 2 magnets pinch it). It’s made of tiny capsules of nickel particles in liquid suspension, it doesn’t take much pressure to rupture these capsules ruining that part of the film :(

4. olig says:

I did some testing with a 3d magnetic sensor here https://ogprojects.wordpress.com/magnetic-field-sensor/
Whats interesting is if you bought a load of them and put them into a grid array then you could see magnetic fields in real time. I just did some testing with the one sensor but you get the idea.

5. w says:

“By complaining about spelling and grammar mistakes, you are encouraging them.”

This is one of my favourite sentences of all time. Can’t quite put my finger on why.

6. mcnugget says:

Brian,

Everything ok? You seem a bit hostile as of late. Just for the record, once you publish any text for the world to see, someone will find a reason to troll the author. I’ve done it a few times only because the article really was rubbish. A good editor puts a smile on (the wide-eyed psycho killer kind) and has something clever to retort back with. Your responses seem excessively abrassive. It’s our job to be the whiny ones, not the editors. This leads me to believe stress levels must be running high at the hackaday office. Fyi, ‘preciate ya.

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