This machine reveals moon phases based on inputted dates

A Maker duo has devised a project that lets moon phases become both tangible and poetic. 

The moon has phases because it orbits earth, which causes the portion we see illuminated to change. And while the moon actually takes 27.3 days to complete an entire go-around, the lunar phase cycle is 29.5 days. As a way to better visualize new, quarter and full moons, Makers Yingjie Bei and Yifan Hu at NYU’s ITP Program have developed an interactive installation that they call Moon Phases. The aptly-dubbed device, which resembles an old-school turntable, lets users simply input a date and see its corresponding moon phase — from the northern hemisphere’s perspective.


“The idea started from my very first processing sketch which is a 2D drawing for moon phases. From there, I started to expand and approach it from different perspective. The moon phases machine is the ultimate work through out the whole journey,” Bei writes.

The project’s structure was inspired by Orrery, a mechanical model of the solar system that predicts the relative positions and motions of planets, as well as the simplicity of changing numbers on a thermostat. This would not only provide viewers with a new way to experience new, quarter, full and even crescent moons, but to do so in a more tangible and poetic manner. Stories about that particular phase are simultaneously displayed through the beautifully-crafted machine’s built-in screen.


How it works is relatively simple. A user selects a date — whether it’s their birthday, a historical event or even hundreds of years into the future — by turning three different knobs, each representing the year, month and day, respectively. An Arduino Mega (ATmega2560) embedded inside the device uses the Processing language to properly calculate and identify the correct phase. From there, the Arduino controls a servo located beneath the machine to rotate the turntable and accurately position the light, which is projected onto the mini cement moon.

Intrigued? You can find a detailed breakdown of the build here, and see it in action below.

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