Portable, Pocket Sized ROMP

Many of you may have read the full sized ROMP instructable, but those of you who didn't, here's a link: https://www.instructables.com/id/E7343C85JWERIE2RED/

As you can see Stormed and I had a nice conversation about the "Random Oscillating Magnetic Pendulum", and he came up with the idea to make it portable. So then we started coming up with ideas on how to do this. Apparently I finished my design first though, so if you see another instructable much like this one posted by Stormed, don't say that this has already been posted, since his design varies from my own and without his comments, I may never have actually thought of this.

After much trial and error, my Pocket ROMP is complete. Now when I go to the DMV and the batteries in my handheld goes dead (cause we all know how long it takes), I can take this out and perhaps even inspire other people there to make their own.

Here's how I built my Portable.

Warning: Do this in a well vented area due to fumes. The soldering iron also becomes hot, so be careful with it.

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Step 1: Materials

Time to gather your materials.

1. Goop or rubber cement (also a small nail to spread with)
2. A round disc magnet
3. Pliers
4. Box Cutter (sharp knife)
5. Strong Wire
6. Marker
7. Altoids Container
8. Soldering iron and solder
9. Thread
10. 9 volt battery (or a small flat piece of metal)
11. Foil insulation or piece of cardboard.

Step 2: Cut the Magnets and Make the Pendulum

1. Take the disc magnet and hold it in the pliers (if you have a second disc magnet, use it to find which sides attract and which repels). Now cut it in half.

2. If you didn't have a second magnet, follow this step. Use the half magnets on each other, do your best to discover which areas attract and which areas repel. Cut the disc so that each smaller magnet only repels or attracts on each side.

3. After you have cut one half of the magnet into smaller magnets, cut another one out of the other side to be used as your pendulum.

4. Now use your marker to mark which sides of the main magnets will repel the side that you've chosen to be used for your pendulum.

5. Cut the pendulum down to size and make a slight cut half way into the magnet (so that one side of the cut is at the bottom, the side that you've chosen to repel off the others, and the other side of the cut is at the top). Cut a piece of thread about 5 inches long (makes it easier to tie the knots).

6. Using the small cut you've just made, insert the thread into it and loop it back up around the magnet and tie.

7. Now take the wire and bend the tip up. Tie the thread (so there's about an inch and a quarter) around the dip in the tip and bend the tip back. Goop up both the tip of the wire and around the magnet's sides and top (not the bottom though).

Step 3: Make the Case

1. Solder the wire into place (mostly in the corner) in the bottom of the case.

2. Take the foil or cardboard (if you use cardboard only use enough to fill the center, about an inch by two should do) an cut it to fit. Goop it into place. The foil allows the cover to close, so I decided to use it.

3. Take the 9 volt battery and take just the casing ( https://www.instructables.com/id/EOGAE2LXOUEP287E6N/ ), cut the casing and flatten it. Now trim it down, so that'll fit into the center of the lid. Goop it so it'll stay there.

Step 4: Finishing Touches and Then Play

1. Now the only thing you need is something to help keep the lid at a level and flat position. I cut a piece of the unused half of the disc magnet and used it on the top of the lid to support it. After I'm finished playing, I just place the magnet inside with the others.

Now you have a completed pocket sized ROMP (I suggest keeping it away from things such as cell phones and ipods).

All you have to do is open the lid and bend the arm into position. Then take the magnets and place them where you feel like it on the platform. Swing the pendulum and watch as it repels through the fields. After you're done, bend the arm back down and position the magnets in a group in the center of the lid (or in with the arm) and close the lid.

As always, improvement ideas are welcomed.

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    16 Discussions

    It may work for awhile, but after a few bends, it may break. Might be able to get away with one of the ones encased in rubber.

    ok. thats what i did, put on lid. i used small neodymium magnets. 12 on lid and used 2 to hold string for pendulum. will post pic as soon as i get pendulum done.

    paper warrior

    13 years ago

    i got one a few years ago, the altoids can was a crater on the moon and the hanging magnet was a flying saucer

    1 reply

    13 years ago

    Haha, nice job. I spent all yesterday finding a camera, then charging the batteries when it died. And am starting as soon as the folks wake up, because if they don't wake up, the power tools will. Since I'm a bigger fan of a small form factor(plus my room is cluttered and mess, as well as tiny), I'm starting the mini one. In a week or two, I might order a bunch of tiny magnets for use with this stuff(5 dollars for 100 really tiny ones). I'm probably going to use an object to hold the magnet, which will then be attached to a piece of string.

    3 replies

    Reply 13 years ago

    I wish you the best of luck, at first I was going to put the arm on the lid, but found out that the magnet was too attracted to the walls (even after I tried to put up a barrier out of Goop and electrician's tape, which I had to tear out). So after much thinking I figured out this design, which raised the platform above the sides of the lid. I may try to make the variable magnets smaller to create smaller fields though and paint the inside so it'll look better. Perhaps even draw the bullseye on the platform. Anyhow, wishing you the best.


    Reply 13 years ago

    And...DONE! A ROMP in an Altoids Apple Sours can =]. I'm going to write up the instructables now, with fancy pictures and everything. I made a few mistake along the way, but can easily be done properly by someone else(by the time I noticed the mistakes, it was too late, and I was too lazy).


    13 years ago

    It's a random oscillating magnetic pendulum. It creates randomness by taking advantage of the magnetic fields of the magnets. It's just for show mainly. The pendulum just swings about widely. It's kinda cool.


    13 years ago

    It's a random oscillating magnetic pendulum. It creates randomness by taking advantage of the magnetic fields of the magnets. It's just for show mainly. The pendulum just swings about widely. It's kinda cool.


    13 years ago

    What does it do?