A heliostat is a responsive, robotic mirror that tracks the sun in order to redirect its light

As the central project of my Master’s in Engineering, I designed and built a custom heliostat for my New York City apartment — a working prototype for distributed daylight redirection.

Using an Arduino microcontroller, I programmed a dual-axis tracking system capable of continuously calculating the sun’s position and recalibrating in real time. The X-axis (azimuth) rotation traces the sun’s daily path using astronomical data derived from the Julian Date API. The Y-axis (altitude) tilt adjusts the mirror’s angle to redirect incident sunlight into the interior ceiling.

Constructed from repurposed and found materials, the kinetic sculpture clangs like a chariot in motion, scattering  light wherever it turns.

Developed in New York City — where vertical growth and zoning laws regulate access to light — the project proposes small-scale, distributed heliostat systems for reclaiming daylight in increasingly occluded environments.

In November 2023, I returned to this research to present Pushing Daylight at NYU’s Environmental and Racial Justice Network (ERJN), examining the politics of solar access and daylight zoning in dense cities.

Fabrication Process

Effect

ITP Thesis Week 2023 - Stela Xhiku from ITP_NYU on Vimeo.