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.