Hackaday’s portal gun actually levitates a companion cube

I was out to lunch with a couple friends, brainstorming ideas for fun projects when one of them says “Wouldn’t it be cool if we could build a working gravity gun?”. We all immediately concurred that while it would in fact be cool, it is also a silly proposition. However, only a few seconds later, I realized we could do a display piece that emulated this concept very easily. Floating magnetic globes have been around for quite some time.

I determined I would tear the guts out of a stock floating globe and mount it on a portal gun, since they’re easier to find than a gravity gun. I would also build a custom companion cube to be the correct size and weight necessary.

The Levitation System

I started off with a StellaNova magnetic levitating globe. I chose the larger version that is roughly 8″. My assumption was that this one would be able to hold a little more weight than the smaller version.

Prying the coil out of the metal frame turned out to be difficult and actually resulted in a damaged coil that I had to repair. If you were to replicate this, I’d suggest cutting the entire metal case that contains the coil from the frame instead of trying to remove just the coil.

Once I had the coil out, I tore the strong magnet out of the top of the globe. This globe actually has a magnet in the base that helps stabilize it during levitation so I knew I was going to have to tweak my companion cube to get the weight just right. As you can see, my process is purely scientific and extremely precise.

The portal gun

I really wanted to make my own portal gun for this. My schedule and my ego fought hard on this subject and ultimately my schedule won. While I feel like I could have built a fantastic portal gun, there’s no way I could have done it in a reasonable amount of time and gotten as nice of results as just buying the portal gun props available at toy stores.

When initially mounted the coil on the gun, I found that the “arms” were far too flexible. I had to reinforce the arm somehow. The option I chose was simply to bend a piece of steel to the correct shape and strap it to the underside of the “arm”.

I made a cardboard model to test weight and size of the companion cube and got the system working on the portal gun.

The Cube

At this point, the entire thing is working. I’m far too excited to wait for some kind of store bought cube to arrive and attempt to get it to the correct weight. That’s assuming I could find one the right size. So, I made my own out of foam. Admittedly, it isn’t the best looking companion cube in the world.  If I were to take this further, I’d probably sculpt one and make a mold so that I could make my own solid foam companion cube.

A single huge improvement:

I started off thinking that the final product would be a portal gun that you could hold while it levitated a cube. This meant that I needed to actually mount the coil that suspends the floating cube on to the portal gun. As you can see in the video, it is a fairly visible modification. You can see the coil, wires, and reinforcement on the top arm of the portal gun. Once it was built however, I found that I couldn’t hold it still enough to maintain the levitation.

Since holding it is officially not going to happen, I realized I could have done this in a more aesthetically pleasing manner. Instead of using the type of  floating globe that dangles the magnet below a coil, I could have used one with a magnetic base that floats the magnet above the coil. This would have left the portal gun completely un-modified.


I wanted to give a special thanks to Vintage Stock in Springfield Missouri (the one on Glenstone), who let me bring the system in and show it off until the hall effect sensor finally got smashed too many times and the cube wouldn’t levitate.


  1. sneakypoo says:

    God dammit, now I want to play Portal again…

  2. jakeb says:

    awesome… just awesome…

  3. bleh says:

    this makes me happy.

  4. dfjd says:

    huge != cool

  5. Reggie says:

    It’s a proof of concept, if you’re a smart hacker, you’ll build your own, holding it all together with jam and newspaper!!!

  6. DYe says:


  7. JOJIM says:


  8. JOJIM says:

    Awesome hack! This is a pretty cool concept. Even though it’s been around awhile nothing like adding some shine and a cool enclosure.

  9. Steph says:

    While some people may be complaining about the merit of the hack, it’s still a hack, and it looks damn cool too!

    And I forgot to say it yesterday, but Happy Birthday Caleb!

  10. Haku says:

    You have a Portal gun!


    Oh hey check this pic out my brother snapped whilst out and about: http://www.haku.co.uk/pics/PortalClose.jpg (unedited)

  11. Jeri Ellsworth says:

    Very cool. Sent it to the internal mailing list at work.

  12. n0lkk says:

    Different Stokes for different folks, but with this at the top pf the page I about moved on
    “Especially since about half of the pages haven’t been updated over ten years and half the links are broken.

    Well, bookmark this site anyway, as I plan to update it as soon as I can find some free time.”
    Not the most enticing way to inspire new visitors however I scrolled through the opening page anyway, still nothing to compel me to explore much further. For most hackman implies we would see the projects of hackman or others front & center on the opening page, but one has to scroll ro the bottom to get to an index where we can select areas of interest
    I compare that the hacakaday, where I week can go by, and quickly catch up on the posts by tapping the sown arrow key. A side bar allows me to catch up on posts of particular topic interests quicker yet. I did bookmark bookman, but I can’t see myself visiting it regularly.

  13. Anon says:

    Just disguise the magnet as a potato?

  14. Jon Vincent says:

    Hey, now we can build a working gravity gun. It just needs to shoot the object around.

  15. James says:

    Ok this is freakin awesome.. I haven’t looked at this site in a long time, and they got published everywhere and reminded me how much I <3 this site :) keep it up!

    Now lets see about buying these things…

  16. danm36 says:

    How about, instead of using that weighty and obtrusive coil, using three small but powerful standard magnets at the same polarity pointing towards the ‘hold area’ of the gun attached to each arm, and the cube made of a magnetic metal/contains a magnetic metal/contains another strong magnet. The cube would then be physically pushed inside the claws, perhaps making movement more possible.

    • leafy says:

      think more carefully about the forces involved and you’ll understand why that couldn’t work

      • Sasha says:

        Actually, it WOULD work. Leafy, you clearly do not understand the forces involved yourself. In fact, it is VERY easy to make it work with the right size magnets. A maglev train essentially uses this layout of magnets. You have a magnetic “deadzone” at the center of the region of magnetic force. The object (the companion cube) thus “floats” in the center of the three magnetic fields. There maybe some slight fluctuations due to the occasional cancelling of two or more magnetic fields, but it is only slight and only very short-lived. It is similar to the effect of moving air on an object. Ever turned a vacuum cleaner hose straight up and suspended a ball in the stream of air? That is the same result you would get with three magnets arranged around a point.

  17. David Small says:

    “I had to reinforce the arm somehow. The option I chose was simply to bend a piece of steel to the correct shape and strap it to the underside of the arm. — Jeri Ellsworth (see above)

    Every time she talks like that, my heart goes pitter patter. To really make my day, maybe she’ll get back to putting a roll cage into a race car, measuring, bending, cutting, welding… Ah, wait a second, I’m singing a Journey song here (“Lovin, Touchin, Squeezin”)!

    I have to stop, the room here is getting too warm.

    (I’m not hassling Jeri here, quite the reverse. I have a great deal of respect for her. Here she succeeded at a magnetic suspension project, and I know how hard it is to stabilize those, because I tried to do the same thing, and didn’t get it stable before I ran out of time.)

    Keep on rockin’.

    — Dave Small

  18. n0lkk says:

    Shouldn’t step 2 be modify( hack) them, with step 3 being combine them? In regards to step one; show us a hacker that claims they never purcased anything off the shelf to get started on an idea, sorry respectfully we may have been lied to. That leaves step 4:Profit?; I certainly hope so, or at the very least not costing those who run Hackaday to the point they have to reconsider if there efforts are the best course of action for themselvess & their families. Both hHuge, and hack are relative terms , subject to personal opinion. Here’s mine All hacks are “builds” Build has distinct long time definition, so it isn’t a relative term. This build is constructed from items that have been hacked. INMO a hack? Yes. A huge hack? No. Not that I don’t appreciate the effort.

  19. n0lkk says:

    Keeping in tune with the season. I am N0LKK, I approve of this blog entry made by Caleb.

  20. DMF says:

    How about building a companion cube around a ducted quadcopter, and have it follow where the grav gun is pointing.

  21. meh679 says:

    I just wanted to leave a comment for you guys to possibly consider. This would be a much more in-depth project and would require a lot of research time and money but, it would be unfathomably cool if you could combine your idea with this: http://www.ted.com/talks/boaz_almog_levitates_a_superconductor.html It’s a magnet that in unison with a semiconductor uses “quantum locking” to “levitate” the semi-conductor. It would be super cool if you guys could do that!

  22. Eax says:

    What’s the music used here?

  23. Hack Man says:

    I am not associated with that website.

  24. MrX says:

    combine? this is not HL2

  25. brnrubbr says:

    Caleb = my hero. Very cool

  26. Robert says:

    “I could have used one with a magnetic base that floats the magnet above the coil. This would have left the portal gun completely un-modified.”

    How were you thinking of doing this? Would you have just incorporated this coil into a display base or something?

  27. Vergules says:

    This is cool. I want one

  28. Cyril says:

    from: http://hackaday.com/2012/08/11/announcing-international-hack-day-august-11th/

    Repurpose, reuse, invent, and recycle. Not just duct taping stuff together, it applies to code, ideas, whatever. — Ian Lesnet, Dangerous Prototypes

    Step 3: Lower the bar to the Honey Boo Boo mark then bask in the glory of sycophantic praises – it’s SASSY!

    see also: http://thereifixedit.com

  29. Faizan Ali says:

    Gaming is every where, athletes do not regret.

  30. Hack-a-Tear says:

    Withhold thine self. This device is still ‘cool’.

  31. Yoka says:

    HEy dudes,
    I enjoy you show a lot.
    I also enjoy music. What’s the sampled hiphop soundtrack called on this one?

  32. Chad says:

    Hey Caleb,

    I just wanted to say, awesome creation. If I ever get a fireplace, I want a gravity gun just like this to adorn the mantle… right below the nude self portrait of myself.

  33. YS says:

    When I first saw it, I thought of something Bernoulli’s principle-based.

  34. bwheel says:

    This hack is so cool. What if… you could improve sleep by waking up on the perfect rem cycle. Lets see where you go with that one.

  35. F4R4D4Y says:

    Simple hack; if any mod makes one person say “cool”, it’s a successful hack. Grats to that!

    That said, portal is just “meh”

  36. skyrimruinedmylife says:

    the mini replica gun has been sitting on my shelf, collecting dust… after seeing this hack, ive decided to give it a whirl (also bought a smaller globe for only $10, same brand). what tools did you use to take the coil out of the globe stand? if you can please give me some tips that would be great since i tend to have the patience of an wildebeast, my globe would probably break in a matter of minutes and subsequently have me yelling fus roh dah at the top of my lungs like a crazed madman….

    Great hack by the way, it had me fan girling!

    • Caleb Kraft says:

      I highly suggest leaving the coil in that little metal part that it is in. You could use a dremel or hack saw to cut the pipe that leads to it. Be careful though, there’s a wire in that pipe.

      However, since you can’t actually lift the gun while it is levitating, you could just build a cube and hover it right in front of the gun for almost as good of an effect.

  37. James Hopton says:

    Aha! Seeing a recent reply from the builder, thought i would jump in with a question of my own. How much does the globe weigh??? Ive got the same base that i got from a goodwill outlet store (if youve never been to one, you dont know what youre missing. Broken things and parts galore) and ive been trying to weight a plastic penguin with a magnet in his dome and make him float but i cant seem to get it anywhere near correct. Did you reuse any of the electronics from the stellanova base or just the coil? Great job on this one btw.

  38. Mikey says:

    Would be cool if all three prongs had mcu controlled magnet coils that could hold a better grip on a metal companion cube — also if there was a coil in the center, so that you could quickly create a magnetic push which would toss the cube out (like in the game) — or help in attracting one (for instance, from the table).

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