P-153: Orrery Update 1

First of all, an Orrery is a model of the solar system, which represents the positions of the planets, and sometimes their moons, using a system of cogs and wheels, similiar to the way a clock does with time.

I have designed the mechanism for the Orrery and calculated the sizes of all of the cogs and wheels. I have also created a concept model in AutoDesk Inventor showing how the different sets of gears would work.

I intend to have one small electric motor powering the main gear assembly, consisting of one gear for each planet, fixed together. This gear assembly will in turn be connected to another gear assembly, also with one gear for each planet, but this one will have the cogs free rotating. Each cog on the second wheel will rotate at the speed that the planet orbits the sun in reality. The motor and the timing of it will be controlled by an Arduino microcontroller.

There will be a number of shafts on the second gear asembly, one for each planet, each inside one another. These will connect to the arms which hold the models of the planets. Googling “Copernican Planetary Orrery” will bring up some results of the kind of device I am constructing. I will post more pictures as I finalise the design.

I am not certain how accurate I can make this, given the manufacturing constraints, and the fact that plantary orbits are actually elliptical (See Keplers Laws) in real life, not circular, but I should be able to make a fairly good approximation of an astronomical clock.