Tired of a Household Chore, This 13-Year-Old Built a $25 Solar Tracker That Boosts Output by 20% — Without Using Electricity

Most solar panels stand still while the sun moves. But a Massachusetts seventh grader fixed the problem with a low-cost solution and gravity.

Every great invention starts with a problem that needs fixing, and for 13-year-old Jason Chang, that problem was Christmas lights.

His mother repeatedly asked him to head outside and manually tilt the family’s solar-powered holiday decorations so they would stay pointed at the sun. Annoyed by the routine in freezing weather, the seventh grader at Worcester Academy in Massachusetts decided to engineer his way out of the chore.

“I got kind of frustrated,” Chang told CBS Boston. “What if I could fix this problem?”

Over the next year, the backyard annoyance evolved into a device that could one day find its way into millions of solar panels. The device in question is a completely passive, motor-free solar tracker built for less than $25.

In outdoor head-to-head testing, Chang’s prototype increased solar panel voltage output by roughly 20% compared to a standard fixed panel — earning him the title of National STEM Champion and an invitation to showcase his work in Washington, D.C.

The Hidden Flaw in Standard Solar Panels

Most residential and off-grid solar panels are bolted into a single, fixed position. You of course put the panels on the side of the roof that gets the most sun over the course of the day and that’s kinda it. Yet, because the sun arcs across the sky from east to west, a stationary panel only captures direct, perpendicular sunlight for a small window during the middle of the day.

During the morning and late afternoon, sunlight hits the panel at steep angles, leaving up to 20% of potential energy on the table.

Commercial solar farms solve this challenge with motorized single- or dual-axis trackers driven by electronic sensors and actuators, but these systems carry steep drawbacks for everyday or off-grid setups. Beyond adding hundreds or even thousands of dollars to an installation’s upfront cost, their motorized components create a parasitic energy drain by consuming a portion of the very electricity the panels produce.

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Compounding both issues is the constant risk of mechanical failure, as complex gears and sensitive electronics inevitably struggle to hold up against harsh outdoor environments.

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How It Works: Water, Gravity, and a Seesaw

Instead of chasing the sun with expensive motors, Chang leaned into one of the oldest mechanisms in history — gravity and fluid dynamics, reminiscent of an ancient water clock.

His tracker mounts a solar panel onto a balanced, seesaw-style frame crafted from inexpensive and recycled materials, completely replacing optical sensors with a precisely calibrated fluid system. Operation begins simply at the start of the day when the user pulls a stopper from an upper water reservoir, initiating a steady, tightly controlled drip into a collection bucket hanging from one side of the frame. As this bucket gradually fills, the shifting weight slowly tips the seesaw downward, guiding the solar panel in a smooth, continuous tilt across the sky that mirrors the sun’s natural arc.

“All you have to do is pull on the plug, and the water starts flowing,” Chang explained. “Over time, it will add water slowly into the bucket, weighing the panel down gradually to follow the sun’s movement.”

Getting the panel to match the earth’s rotation without tipping too fast or stalling took more than a year of trial and error.

“The hardest part was the fluid control frame,” Chang noted. “It has to be very precise — the measurements have to be exact for the panel to move correctly.”

Why a $25 Price Tag Could Change Off-Grid Power

When Chang placed his gravity-powered tracker outside next to a conventional stationary panel, the moving panel generated approximately 20% more voltage over the course of the test.

While a 20% voltage bump is impressive for a middle-school science project, the real breakthrough lies in the system’s cost-to-performance ratio. Because the tracker requires zero electricity to run and relies on everyday parts that cost under $25, its practical utility stretches far beyond suburban holiday lights.

In off-grid rural communities across developing regions — where families frequently depend on a solitary solar panel to charge phones, illuminate LED lamps, or keep critical medical refrigerators running — squeezing an extra 20% from existing infrastructure without buying additional hardware is transformative. That same low-cost resilience could make it a valuable tool in disaster relief zones, where hurricanes or earthquakes routinely knock out centralized power grids, leaving emergency responders desperate for rugged, field-repairable setups that operate reliably without delicate circuit boards.

“I hope my project can help people around the world to provide more electricity,” Chang said. “Since it’s very low cost, I believe that it can be made anywhere around the world.”

The Winter Hurdle — And What’s Next

Like any good engineer, Chang is quick to point out his prototype’s current limitations. One of them is New England winters. Because the mechanism relies on liquid water, freezing temperatures bring the seesaw to a halt.

He is already engineering a next-generation, all-weather version designed to operate year-round in sub-zero conditions, ahead of his trip to present the project at the National STEM Festival in Washington, D.C.

When CBS Boston meteorologist Jacob Wycoff surprised Chang in class with the news that he had been selected as one of the nation’s top young innovators, National STEM Festival co-founder Jenny Buccos called the 13-year-old one of “the 55 reasons to believe the future is in incredible hands.”

As for the kid who just wanted a break from adjusting his mom’s Christmas lights, the experience has already shaped his career plans — and his life philosophy.

“I think most problems in life, instead of working hard, you should work smarter,” Chang said. “When I’m older, I want to be an entrepreneur, create products, and make everyone’s life easier.”