Meridian Orrery — A 3D Printed Solar System on Your Desk Powered by ESP32C3 🌍🪐
Introduction
What if you could print an entire solar system on your desk? The Meridian Orrery makes this possible with just an ESP32C3, a 3D printer, and some clever engineering. This open-source project puts all 8 planets (plus Earth's moon) in motion—calculating their positions locally, with no internet required.
What Is It?
The Meridian Orrery is a fully functional orrery — a mechanical model of the solar system — built entirely with 3D-printed parts and an ESP32C3 microcontroller. Each planet orbits the sun at accurate relative speeds, and Earth's moon actually orbits Earth too.
The magic? It's all computed offline directly on the ESP32C3 using astronomical algorithms. No NASA API, no Wi-Fi, no external data sources.
Key Components
| Component | Role |
|---|---|
| ESP32C3 Super Mini | Runs astronomical simulation locally |
| DS3231 RTC | Precision timekeeping for orbital calculations |
| TMC2209 | Stepper motor driver |
| 3D Printed Parts | Planets, gears, and mechanical linkages |
| Ball head pins | Planet mounting posts |
| Reed switch + magnet | Homing sensor for calibration |
What Makes It Special
🌙 Moon Gear Mechanism
The moon orbits Earth via a 1:11 gear ratio (6 teeth inside a 66-tooth ring). It's a mechanical approximation, but the system uses software corrections during the nightly homing sequence to achieve surprisingly accurate results.
🔧 No Soldering Required!
The design prioritizes accessibility. You only need a 3D printer, super glue, sandpaper, and a soldering iron for the pin headers. It's beginner-friendly while still being technically impressive.
🌐 Completely Offline
Orbital positions are calculated using on-chip algorithms—no cloud dependency, no API keys, no latency. Once set up, it runs anywhere.
Real-World Skills You Practice
- Orbital mechanics (how planets actually move)
- Stepper motor control (precise positioning with TMC2209)
- Real-time clock (DS3231 for accurate timekeeping)
- Mechanical design (gear ratios, 3D modeling)
- Embedded programming (Arduino IDE, RTClib)
Build It Yourself
Full instructions, STL files, and the Arduino code are available on Instructables:
-
Link:
https://www.instructables.com/Meridian-Orrery/
Search "Meridian Orrery ESP32" on YouTube for a working demo.
Why This Matters
The Meridian Orrery is a perfect example of how maker tools have democratized complex engineering. An ESP32C3 costs a few dollars, a 3D printer is increasingly common, and suddenly you can build something that museums used to charge admission for.
It's astronomy meets maker culture—a tangible, beautiful reminder that the universe runs on math.