Summary
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Meridian Orrery uses an ESP32, 3D parts, magnets and motors to build an automatically updating tabletop solar system.
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It uses an RTC ESP32C3 and DS3231 to calculate planet positions offline after a one-time calibration.
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The clever 1:11 gear ratio makes a small Moon orbit the Earth precisely while the rings and planets align every night.
There’s something innately cool about mixing ESP32 and 3D printing technology with the cosmos. After all, humanity has been gazing at the planets and the moon for millennia, so depicting the positions of the celestial bodies in the comfort of your own living room has a special vibe.
If you want to build your own planetarium, I have the project for you. Someone has created a complete solar system model that combines the ESP32, some 3D printed parts, and magnets, and is designed to be as easy to manufacture as possible.
Meridian Orrery is a planetary model that you can build yourself
It even comes with a tiny moon orbiting the Earth.
This incredible project is the idea of illusionmanager in Instructableswho calls his device Meridian Orrery. It looks complicated, but the creator is actually very proud of how simple it is under the hood. To do this, you just need an ESP32C3 Super Mini, some motors and magnets, sandpaper, a 3D printer, and a DS3231 real-time clock to monitor the current time. Once you set the date and time correctly, Meridian Orrery can automatically determine where the planets are without an internet connection.
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The calibration process is quite fascinating and you can see it in action in the video above. Once a night, the device will begin to rotate the rings until they are all aligned on a spring equinox. Once the planets are in line, the device gets to work “placing” each planet in a back and forth motion until they are all in the right place.
But what about the miniature moon orbiting the Earth? Well, illusionmanager implemented a smart solution:
It has a small 6-tooth gear that runs inside a 66-tooth ring. When the Earth’s ring moves, the Moon rotates around it. With this ratio of 1:11, one complete rotation of the Earth causes the Moon to end up in exactly the same place. In other words, when the system has calculated the Earth’s rotation, it also knows where the Moon would end up.
Honestly, looking at the Instructables page, it really doesn’t seem that complicated to make. It looks like illusionmanager did all the heavy lifting of creating the mechanism and programming everything, and you just need to put everything in place. Plus, there’s no better way to start a conversation than a planetarium you’ve built yourself.
