I first came across this idea when I stumbled upon this site: http://www.thinkgeek.com/geektoys/cubegoodies/6758/
But I didn't feel like paying for something that I could just as easily make. I first tried this using a cardboard box as my base and it worked, but the box eventually tore. So now here I am to remake a better base and to show you how you can get more use out of those magnetic darts.
The materials you'll need are:
1. A Magnetic Dart set
2. A flat wooden board (8" is long enough)
3. A 3/32" and a 9/32" drill bit
4. A Drill of some sort
5. A wire coat hanger
6. Twine (string, thread, fishing line, etc.)
8. A marker (optional)
9. Tape measurer
There is now a movie posted above the comments (it also can be found at the last step). The point behind this whole instructable (I feel obligated to mention this now) is to make a toy that both the young and old can enjoy. You move the magnetic fields (either repel or attract) around by deciding where you want each of the magnets, then let the pendulum swing to find out how the magnetic fields you've just created will cause the overhead magnet to react.
You could have just made a field to make it stand still which will be caused either by charges that are alike to the pendulum in a circle forcing it to stay between them or a magnet with an opposite charge of the pendulum that will attract the pendulum to it. You also could have made it do a dance around the base by placing magnets of opposite charges near each other and spread out making the pendulum swing randomly through the invisible fields.
Make one of these for a child to teach them about how magnets repel and attract each other (I suggest using a better board than I did and paint it). Could even be used as a science fair project if you feel like recording the locations of where each type of magnet was and how the pendulum reacted to each trial.
Forgot the all mighty WARNING label.
Warning: Scissors are sharp. Twine can tangle and choke. Small objects found within this instructable are not suitable for eating, so please do not give to small children nor shall you eat anything found within this instructable.
I will not be held responsible for the actions of others.
Note: There is now an improved paint picture below for making this ROMP. Some credit must be given to Stormed (see comments below).
Step 1: Steal the Magnets, Give Them Each a Pool
2. Put the 9/32" drill bit into the drill (If you're brave, use the old hand cranking one like I did. My cordless "power" one is dead right now). Start drilling into the board. Space the holes about an inch apart (from the centers) and make a 4x7 pattern. Check each hole with one of the magnet heads to make sure they're deep enough (you could always drill straight through, but I think it looks better without the holes going all the way).
Step 2: Hanger Attachment
Now that you're finished drilling the holes, you're board should look similiar to mine.
1. Now take you're coat hanger and either bend until it breaks or cut it around 1'4". Bend the top into an "N" shape to make the hanging point.
2. Take the 9/32" bit out and replace it with the 3/32" bit. Drill a hole into the center (straight through) but along the side of the board. If you're confused look to the picture below to find out.
3. Push the hanger through the hole you have just made until about an inch is sticking out the other side.
4. Cut a groove into the bottom of the board (I used the drill sideways to cut the groove) and bend the wire over the side of the board and twist it around into the groove. You should now have a tight fit and a snug fitting hanger.
Step 3: Attach Pendulum and Enjoy...
1. Take the twine and cut off 6" (you can trim later if needed) with the scissors.
2. Using the 3/32" drill bit, drill a small hole near the top of the dart. Now thread the twine through and tie (I only tied it once, in case I feel like playing darts, it wouldn't be hard to undo the knot and is strong enough for this).
3. Tie the other end up around the hanger (pendulum's magnet should be about 1.25" away from the board). Trim extra twine off.
4. Install your magnets into the holes and create your own chaos. You can attach the pendulum to the hanger while you create your maze, so it won't stick to the magnets while you move them. Swing the pendulum from one side and watch to see what pattern it will follow.
There is one more thing I would like to do to improve this and that is to drill some holes in between the other holes so it'll look something like this (+ = the holes):
This will allow you to place opposite magnets closer together to cause more messed up fields.
Hope you've enjoyed this instructable and hope to hear some feedback. Don't forget to watch the movie below to see one of the patterns I made. Improvement ideas are always welcome.
And you thought I was going to teach you how to play darts...
Almost forgot to place the hanger protection up.
More or less all this will do is prevent the pendulum from sticking to the hanger while it's swinging.
Materials: Foil Insulation (a piece of plastic will also work) and tape
Put the foil around the bottom of the hanger and tape it there. Simple as that. Now the pendulum won't stick to the hanger while you're trying out your magnet maze.