Arduino - Magnet levitation

My first Arduino project, floating a permanent magnet using an electromagnet that pulls it up. The power on the coil is regulated by an Arduino Duemilanove board. The only sensor is a Hall effect sensor at the bottom of the electromagnet. Detailed description at http://mekonik.wordpress.com/2009/03/17/arduino-magnet-levitation/, more pictures at http://mekonik.wordpress.com/2009/03/02/my-first-arduino-project/

Category:

Science & Technology

Tags:

• arduino
• magnet
• levitation
• floating
• electromagnet
• hall
• effect

[lecorfec]

Très joli, très instructif!!!

What is the resolution of your Hall sensor in your project and in a normal environnement (without "parasite magnetic field") ? I mean in term of output variation/ position variation dVout /d(x)

What is the working range of the Hall sensor with a standard NeFBo magnet?

thanks again for your contribution!

[npozar]

@lecorfec Hey, thanks for the interest. I actually don't remember exactly, it was such a long time ago. See my blog post for more details (linked from the video description). I used an external amplifier to increase the sensitivity and to use the whole range of Arduino analog inputs.

[CSPhysics]

VERY COOL! Are you using a Hall Effect Sensor to give feedback to the electromagnet?

[npozar]

@CSPhysics Thanks a lot. Yep, hall effect sensor it is, inside the ugly clay patch ;)

[iwan0t0smith]

You could probably get away with just using the one coil and scrapping the hall probe. If you can measure the current accurately going through the coil you will be able to measure whether or not the magnet is moving since the magnet will induce a current in the coil and hence change the current going through the coil. By passing this data back into the arduino you could then change the current from the battery to change the strength of the magnet

[npozar]

@iwan0t0smith Thanks for the idea. The reason why this would be quite hard to implement though is that the current on the coil has to be adjusted based on the magnet's current position. Reading the induced current on the coil as you suggest can give you velocity only. One then integrate which would lead to an increased error over time. And the system is very unstable (it was damn hard to make this work as it is), with a lot of noise (such as 60Hz from the grid)...

[npozar]

@iwan0t0smith Not to forget, once the magnet is moving in either direction so that a current is generated and one wants to do something about it to prevent the motion, it's too late. It's takes some time to energize the coil (around ~50ms in my case), enough time for the magnet to fall.

[RunawayRed]

This is relevant to my interests.

[npozar]

It's an unstable system, that's why. If you didn't need any feedback at all, you could do the same thing with 2 permanent magnets. Post a video if you succeed.

[freitasnetuno]

thats pretty

[josefbrettl]

Nechcete pr nas vyrobit vzorek linearniho pohonu s almag civkou, civkami, rizeny arduinem?

[plazmafeld]

Great, now can you build a frame for the magnet an big enuff to stand in, an steer us around floating on the earths magnetic field?

[coltononline]

I remember making one of these from a Nuts and Volts article. I was so stoked when I got it to work.

[kikishai]

dude can you post a video on how to make that elivating?

[DerUnbekannte]

great job!

[havocdaemon]

Now that was an awesome idea! Thanks for the vid!

[TD47]

YES!!! COMPLEX ANALYSIS! The bane of my existence.

Prove: e^jTh = 1 ftw!