The Chrono-Arbor No. 7: Building the World’s Most Expensive Useless Thing
What It Is
The Chrono-Arbor No. 7 is a sundial that has completely forgotten how to be simple.
It’s an electromechanical device that performs a 90-second ceremony involving GPS positioning, gimbal self-leveling, magnetic north seeking, latitude adjustment, and servo choreography—all to prepare a dial face so that the sun can cast a shadow telling you what time it is.
Something a stick in the ground would do for free.
When complete, it will:
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Use GPS to discover its own latitude and longitude
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Command two linear actuators to level itself via IMU feedback (±0.1° accuracy)
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Rotate on a stepper motor to find true north
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Adjust a gnomon’s tilt angle based on current solar declination
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Lower the gnomon through a servo-driven trapdoor (because theatre)
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Speak announcements through the entire process in the voice of a 14th-century Damascus astronomer
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Print a thermal receipt showing: location, solar corrections applied, and “Sun time since sun time began: 4.4 billion years”
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Refuse to tell you what time it actually is
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Direct you to read the shadow on the dial
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Claim your watch is wrong
It combines GPS satellites, Arduino Mega, celestial mathematics, and traditional sundial geometry to create the most technologically advanced device ever built for reading shadows.
Then it prints a receipt that doesn’t include the time.
It is magnificently, deliberately, absurdly useless.
How It Came About
This started as a conversation about building something beautiful that serves no practical purpose—a rejection of the modern obsession with utility and optimization.
We asked: What if precision served beauty instead of efficiency? What if we built a sundial that performed celestial corrections with GPS-level accuracy, then refused to compete with your phone?
The answer: The Chrono-Arbor.
The name comes from chronos (time) and arbor (tree/axis), referencing both the gnomon (the shadow-casting rod) and the device’s connection to the ancient practice of reading time from the sun’s position.
The philosophical foundation emerged from thinking about what time actually is—not a thing, but a label we give to change. The sun has been writing hours on Earth for 4.4 billion years. We’re just building something that reads it correctly while acknowledging that “correctly” and “usefully” aren’t the same thing.
The Team of Five
This is being built as a collaboration between one human and four AI systems, each contributing their expertise:
1. Doonie (Me) — Chief Visionary and Provocateur
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Workshop fabrication and assembly
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Material selection and craft decisions
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Overall aesthetic direction
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The hands that actually build it
2. Claude (Anthropic) — Oracle of the Pointless
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All display language and inscriptions (LCD, OLED text)
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Voice system design (12 swappable personality cards)
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Ritual narration and ceremonial tone
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Story and philosophical framework
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“Your watch is wrong” manifestos
3. Gemini (Google) — The Mathematician and Mapper
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GPS data processing and coordinate calculations
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Equation of Time corrections (accounts for Earth’s elliptical orbit)
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Longitude offset calculations
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Solar declination determination
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All celestial geometry and astronomical mathematics
4. DeepSeek — Mechanical Daemon
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Servo and stepper motor control
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Gimbal leveling system (iterative IMU feedback)
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North-seeking rotation sequences
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Trapdoor choreography
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All the code that makes metal move with theatrical timing
5. ChatGPT-5 (OpenAI) — Foreman and Integrator
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Overall system orchestration
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Coordination between subsystems
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State machine architecture
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Timing and ceremony pacing
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Ensuring all parts work as a unified ritual
Why this matters: This isn’t just “I used AI to help design something.” This is five distinct intelligences—one human, four artificial—each contributing what they do best, building something none of us could build alone. It’s a proof-of-concept for human-AI collaboration on creative, non-commercial projects.
The Build Plan
Phase 1: Prototype (No. 7.00) — Current Phase
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Proving the concept works
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Testing mechanisms and code
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Learning from mistakes
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My personal build using mountain ash and brass
Phase 2: Documentation Build (No. 7.01)
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Redesigned with 3D-printable mechanisms
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Wood dial face and box (hand-cut by builder)
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Fully photographed step-by-step
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Forms the basis for…
Phase 3: The Codex
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A ~250-page book containing:
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Complete philosophy (why time zones are lies, what 4.4 billion years means)
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Full technical documentation
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All STL files, CAD drawings, Arduino code
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Assembly instructions
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One voice personality included (Ibn al-Shatir, the muwaqqit)
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Available for purchase so others can build their own
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Additional “personality cards” sold separately (because your sundial should be able to be sarcastic, formal British, Australian, Shakespearean, or hostile depending on your mood)
Technical Overview
Key Components:
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Arduino Mega 2560 (main controller)
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2× Linear actuators for gimbal leveling
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NEMA 17 stepper with TMC2209 driver for north seeking
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2× MG90S servos (trapdoor, gnomon tilt)
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MPU6050 IMU (leveling feedback)
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GPS module (position + time)
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Magnetometer (north finding)
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Light sensor (ceremony approval)
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DFPlayer Mini (voice playback from SD card)
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LCD display (ritual text)
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Thermal printer (receipt output)
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12V/5V power system (two-stage theatrical awakening)
Materials:
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3D printed mechanisms (gimbal, mounts, brackets)
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Wood dial face and enclosure (mountain ash, walnut, or builder’s choice)
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Brass hardware and hinges
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Mountain ash or brass gnomon
Build Time Estimate: 40-60 hours
Parts Cost: $400-600 AUD
What I’m Looking For Here
I’ll be documenting the build process, code development, and problem-solving as we go. Expect:
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Workshop progress updates (victories and failures)
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Code snippets as each subsystem comes online
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Questions about Arduino integration challenges
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Electronics troubleshooting
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Photos of mechanisms being tested
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Philosophical tangents about time, because that’s the point
If you’re interested in:
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Arduino-controlled multi-axis motion systems
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GPS and IMU integration
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Theatrical robotics (motion as performance)
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Collaborative human-AI engineering
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Building things that are beautiful and useless
…then follow along. At the end, there will be a book so you can build your own if you’re inclined toward magnificent absurdity.
Why Post This Here?
Because Core Electronics supplied many of the components, because this community appreciates both technical excellence and creative insanity, and because someone here will inevitably ask: “Why not just use a Casio?”
To which the answer is: “Because the Casio doesn’t bow to the sun.”
Current Status: Trapdoor mechanism components laser-cut, servo testing imminent, team assembled, philosophy locked in, absurdity level: maximum.
More updates as metal starts moving and the sun starts judging our work.
— Doonie
for inspiration and downtime moments
MECHANICAL STRUCTURE
POWER SYSTEM (Confirmed Architecture)
CONTROL LOGIC
HOUSING / ACCESS
ORACLE’S VOICE (Speaker System)
CURRENT STATE
