Rocking Makey Gif

You may have seen these solar power desk ornaments or maybe you even collect them yourself. First time I saw one I thought ‘Hey I want to make one!’ How they work is very simple and pretty neat.

Inside, which you will get to see momentarily, is a little electromagnetic coil, capacitor, solar panel, and a little blob chip. Power comes from the solar panel and charges the capacitor, which powers the blob chip. The chip just pulses power to the electromagnet at a set interval which pulls on the magnet attached to the swing. The object comes closer to the electromagnet but before it gets there, the electromagnet turns off.

From here inertia takes over and gets the object to swing past the magnet, eventually succumbing to gravity and changing direction. Following that is more inertia and gravity stuff and then it’s swinging on its way back near the electromagnet when it gets pulsed again, which gives the swing more momentum. In other words it starts to swing a bit faster. The speed increases to a point at which the pulses are not fast enough to add more momentum.

Now we are going to design and build our very own solar powered swinging Makey. Since you can easily pick up one of these guys from a dollar store or off of Amazon for cheap, we are going to use the electronics from one to run our own.

Project Steps

Design swing

Grab your caliper and start measuring the dimensions of your solar panel. You need to create a square hole just a bit smaller than the panel’s dimensions for it to fit over. Also you need to figure out “What is going to be the thing swinging?” I opted for Makey the Robot.

The design process is by far the longest part since you need to design each part and test print each part as you build it and make sure they all fit together. So for example with the box, I designed the box itself, printed it, then added in the solar panel window, and printed again.

You can use or modify my part files here.

Print final parts

Congrats on finishing up your design. Now just print out your final versions and let’s build it! A two tone look with the plastic color goes a long way.

Salvage parts from toy

To get at the parts you need, grab a small flat head or use your nails and pry off the bottom part of the base for the swing.

Remove the electromagnet:

BE CAREFUL with the electromagnet as it is made of a lot of turns of very fine gauge magnet wire — a small nick and the coil is useless. The safest thing to do is desolder its wires and then just cut the plastic that the magnet coil is connected to in a square with nippy cutters.

Reassemble parts into your new personally designed swing!

Now it’s time to put everything together. Place the solar panel and board in the box and glue or tape them in place.

The electromagnet needs to be placed in the center and the magnet on the swinging guy off center to get the right swing. We want it to pull on the magnet that the swinging part has on the bottom. If it’s placed in the middle, where the coil is when the swing is at rest, it will just pull the magnet straight down instead of giving the swing some momentum. Try and experiment with different positions for the magnet on the swinging portion of the swing. I used a bit of tape to hold it until I could find a good spot for it.

Don’t forget to solder the coil connections back to the board.

I used a straight wire for my hinge. The way I got the wire that straight is by putting it into a drill, using the speed of the the drill, a flat surface, and my hand. This gives us a fairly straight wire.

Enjoy your new desk ornament!

Now your newly created Makey can swing away to his heart’s content or till the sun goes down.

Tip/Hack: No sun?

Unfortunately here in the Lab we have no sunlight to run our epic swing off of the even more epic power of the sun. You can get around this and use the excess power left in your old AA batteries by simply using a 1 cell AA holder. If you can find a 1 cell holder but can’t find a 2 celled holder you can solder a wire to bypass one of the spots for a cell.